Gentoo Linux Use Variable Descriptions

1. Global Use Flags

Flag	Description
3dfx	Enable support for Voodoo chipsets, also called as 3DFX and TDFX
3dnow	Adds support for 3dnow multimedia processor instructions
X	Adds support for X11
Xaw3d	Adds support for the 3d athena widget set
a52	Enables support for decoding ATSC A/52 streams used in DVD
aac	Enables support for MPEG-4 AAC Audio
aalib	Adds support for media-libs/aalib (ASCII-Graphics Library)
accessibility	Adds support for accessibility (eg 'at-spi' library)
acl	Adds support for Access Control Lists
acpi	Adds support for Advanced Configuration and Power Interface
adns	Adds support for the adns DNS client library
afs	Adds OpenAFS support (distributed file system)
aim	Enable AIM IM protocol support
alsa	Adds support for media-libs/alsa-lib (Advanced Linux Sound Architecture)
altivec	Adds support for optimizations for G4 and G5/ppc970 processors
ao	Use libao audio output library for sound playback
apache2	Add Apache2 support
apm	Adds APM (Advanced Power Management) support
aqua	Include support for the Mac OS X Aqua (Carbon/Cocoa) GUI
atm	Enable Asynchronous Transfer Mode protocol support
audiofile	Adds support for libaudiofile where applicable
avahi	Add avahi/Zeroconf support
bash-completion	Enable bash-completion support
bcmath	Adds support for libbcmath
berkdb	Adds support for sys-libs/db (Berkeley DB for MySQL)
bidi	Enables bidirectional language support
bindist	Flag to enable or disable options for prebuilt (GRP) packages (eg. due to licensing issues)
blas	Adds support for the virtual/blas numerical library
bluetooth	Enables Bluetooth Support
bootstrap	!!internal use only!! DO NOT SET THIS FLAG YOURSELF!, used during original system bootstrapping [make stage2]
boundschecking	Adds the bounds checking patch by Haj Ten Brugge, this will DISABLE the hardened PIE+SSP patches
branding	Enable Gentoo specific branding
bsf	Enable support for Apache Bean Scripting Framework (dev-java/bsf)
build	!!internal use only!! DO NOT SET THIS FLAG YOURSELF!, used for creating build images and the first half of bootstrapping [make stage1]
bzip2	Use the bzlib compression library
cairo	Enable support for the cairo graphics library
calendar	Adds support for calendars (not using mcal!)
canna	Adds support for the Canna kana to kanji conversion engine
caps	Use Linux capabilities library to control privilege
cdb	Adds support for the CDB database engine from the author of qmail
cdda	Adds Compact Disk Digital Audio (Standard Audio CD) support
cddb	Access cddb servers to retrieve and submit information about compact disks
cdinstall	Copies files from the CD rather than asking the user to copy them, mostly used with games
cdparanoia	Enables cdparanoia (audio CD ripper) support
cdr	Adds support for CD writer hardware
cgi	Add CGI script support
cjk	Adds support for Multi-byte character languages (Chinese, Japanese, Korean)
clamav	Adds support for Clam AntiVirus software (usually with a plugin)
coreaudio	Build the CoreAudio driver on Mac OS X systems
cracklib	Support for cracklib strong password checking
crypt	Add support for encryption -- using mcrypt or gpg where applicable
cscope	Enables cscope interface -- in vim for example
css	Enables reading of encrypted DVDs
ctype	Enables ctype functions
cups	Add support for CUPS (Common Unix Printing System)
curl	Adds support for client-side URL transfer library
curlwrappers	Adds support for using curl in streams
custom-cflags	Build with user-specified CFLAGS (unsupported)
cvs	Enable CVS (Concurrent Versions System) integration
cxx	Builds support for C++ (bindings, extra libraries, code generation, ...)
dbi	Enable dev-db/libdbi (database-independent abstraction layer) support
dbm	Adds support for generic DBM databases
dbus	Enable dbus support for anything that needs it (gpsd, gnomemeeting, etc)
dbx	Adds database abstraction layer
debug	Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see http://www.gentoo.org/proj/en/qa/backtraces.xml
dedicated	Adds support for dedicated game servers (some packages do not provide clients and servers at the same time)
dga	Adds DGA (Direct Graphic Access) support for X
directfb	Adds support for DirectFB layer (library for FB devices)
djvu	support DjVu, a PDF-like document format esp. suited for scanned documents
doc	Adds extra documentation (API, Javadoc, etc). It is recommended to enable per package instead of globally
dri	Enable direct rendering: used for accelerated 3D and some 2D, like DMA
dts	Enables DTS Coherent Acoustics decoder support
dv	Enables support for a codec used by many camcorders
dvb	Adds support for DVB (Digital Video Broadcasting)
dvd	Adds support for DVDs
dvdr	Adds support for DVD writer hardware (e.g. in xcdroast)
eds	Enables support for Evolution-Data-Server (EDS)
emacs	Adds support for GNU Emacs
emboss	Adds support for the European Molecular Biology Open Software Suite
encode	Adds support for encoding of audio or video files
enscript	Add enscript support to colourize code stored in the repository
esd	Adds support for media-sound/esound (Enlightened Sound Daemon)
evo	Adds support for mail-client/evolution
examples	Install examples, usually source code
exif	Adds support for reading EXIF headers from JPEG and TIFF images
expat	Enable the use of dev-libs/expat for XML parsing
fam	Enable FAM (File Alteration Monitor) support
fastcgi	Add support for the FastCGI interface
fbcon	Adds framebuffer support for the console, via the kernel
ffmpeg	Enable ffmpeg-based audio/video codec support
fftw	Use FFTW library for computing Fourier transforms
firebird	Adds support for the Firebird relational database
firefox	Build against Firefox instead of Seamonkey/Mozilla
flac	Adds support for FLAC: Free Lossless Audio Codec
flatfile	Adds dbm support for flat files
fltk	Adds support for the Fast Light Toolkit gui interface
fontconfig	Support for configuring and customizing font access via media-libs/fontconfig
foomaticdb	Adds support for the foomatic printing driver database
fortran	Adds support for fortran (formerly f77)
freetds	Adds support for the TDS protocol to connect to MSSQL/Sybase databases
freewnn	Adds support for FreeWnn kana to kanji conversion engine
frontbase	Adds support for the frontbase sql server
ftp	Adds FTP (File Transfer Protocol) support
gcj	Enable building with gcj (The GNU Compiler for the Javatm Programming Language)
gd	Adds support for media-libs/gd (to generate graphics on the fly)
gdbm	Adds support for sys-libs/gdbm (GNU database libraries)
geoip	Add geoip support for country and city lookup based on IPs
ggi	Adds support for media-libs/libggi (non-X video api/drivers)
gif	Adds GIF image support
gimp	Build a plugin for the GIMP
glut	Build an OpenGL plugin using the GLUT library
gmp	Adds support for dev-libs/gmp (GNU MP library)
gnome	Adds GNOME support
gnome-keyring	Enable support for storing passwords via gnome-keyring
gnuplot	Enable support for gnuplot (data and function plotting)
gnutls	Adds support for net-libs/gnutls (TLS 1.0 and SSL 3.0 support)
gphoto2	Adds digital camera support
gpm	Adds support for sys-libs/gpm (Console-based mouse driver)
gps	Adds support for Global Positioning System
graphviz	Adds support for the Graphviz library
gsl	Use the GNU scientific library for calculations
gsm	Adds support for the gsm lossy speech compression codec
gstreamer	Adds support for media-libs/gstreamer (Streaming media)
gtk	Adds support for x11-libs/gtk+ (The GIMP Toolkit)
gtkhtml	Adds support for gnome-extra/gtkhtml
guile	Adds support for the guile Scheme interpreter
gzip	Compress files with Lempel-Ziv coding (LZ77)
handbook	Enable handbooks generation for KDE4.
hardened	activate default security enhancements for toolchain (gcc, glibc, binutils)
hddtemp	Enable monitoring of hdd temperature (app-admin/hddtemp)
hdf5	Adds support for the Hierarchical Data Format v5
hscolour	Includes coloured haskell sources to generated documentation (dev-haskell/hscolour)
ibm	Add support for IBM ppc64 specific systems
iconv	Enable support for the iconv character set conversion library
icq	Enable ICQ IM protocol support
icu	Enable ICU (Internationalization Components for Unicode) support, using dev-libs/icu
idn	Enable support for Internationalized Domain Names
ieee1394	Enable FireWire/iLink IEEE1394 support (dv, camera, ...)
imagemagick	Enables support for Imagemagick (image converter)
imap	Adds support for IMAP (Internet Mail Application Protocol)
imlib	Adds support for imlib, an image loading and rendering library
infiniband	Enable Infiniband RDMA transport support
inifile	Adds dbm support for .ini files
iodbc	Adds support for iODBC library
ios	Enable support for Apple's iDevice with iOS operating system (iPad, iPhone, iPod, etc)
ipod	Enable support for iPod device access
ipv6	Adds support for IP version 6
iwmmxt	Adds support for optimizations for ARM iwMMXt instructions
jabber	Enable jabber IM protocol support
jack	Adds support for the JACK Audio Connection Kit
java	Adds support for Java
java6	Use Java 1.6 to build package with \|\| ( reduced deps, 1.6 features, source/target 1.6 )
javascript	Enables javascript support
jbig	enables jbig-kit support for tiff, Hylafax, ImageMagick, etc
jingle	Enables voice calls for jabber
joystick	Add support for joysticks in all packages
jpeg	Adds JPEG image support
jpeg2k	Support for JPEG 2000, a wavelet-based image compression format
kde	Adds support for kde-base/kde (K Desktop Enviroment)
kdeprefix	Makes a KDE prefixed install into /usr/kde/${SLOT} if enabled or into /usr (FHS compatible) otherwise
kerberos	Adds kerberos support
kolab	Adds support for the Kolab groupware server
kontact	Enable support for the KDE personal information manager (kde-base/kdepim*)
ladspa	Enables the ability to support ladspa plugins
lame	Prefer using LAME libraries for MP3 encoding support
lapack	Adds support for the virtual/lapack numerical library
lash	Adds LASH Audio Session Handler support
latex	Adds support for LaTeX (typesetting package)
lcms	Adds lcms support (color management engine)
ldap	Adds LDAP support (Lightweight Directory Access Protocol)
libcaca	Add support for colored ASCII-art graphics
libedit	Use the libedit library (replacement for readline)
libffi	Enable support for Foreign Function Interface library
libnotify	Enable desktop notification support
libsamplerate	Build with support for converting sample rates using libsamplerate
libwww	Adds libwww support (General purpose WEB API)
lirc	Adds support for lirc (Linux's Infra-Red Remote Control)
livecd	!!internal use only!! DO NOT SET THIS FLAG YOURSELF!, used during livecd building
lm_sensors	Adds linux lm_sensors (hardware sensors) support
lua	Enable Lua scripting support
lzma	Support for LZMA (de)compression algorithm
lzo	Enables support for lzo compression
m17n-lib	Enable m17n-lib support
mad	Adds support for mad (high-quality mp3 decoder library and cli frontend)
maildir	Adds support for maildir (~/.maildir) style mail spools
matroska	Adds support for the matroska container format (extensions .mkv, .mka and .mks)
matrox	Adds Matrox MGA support to mplayer
mbox	Adds support for mbox (/var/spool/mail) style mail spools
memlimit	Adds memory usage limiting in supporting programs
mhash	Adds support for the mhash library
migemo	Enables migemo support for Japanese
mikmod	Adds libmikmod support to allow playing of SoundTracker-style music files
milter	Adds sendmail mail filter (milter) support
mime	Adds MIME support
minimal	Install a very minimal build (disables, for example, plugins, fonts, most drivers, non-critical features)
mmap	Adds mmap (memory map) support
mms	Support for Microsoft Media Server (MMS) streams
mmx	Adds support for optimizations for Pentium MMX and Athlon class processors
mng	Adds support for libmng (MNG images)
modplug	Adds libmodplug support
modules	Build the kernel modules
mono	Build Mono bindings to support dotnet type stuff
motif	Adds support for the Motif toolkit
mozilla	Adds support for the Mozilla web-browser
mp3	Add support for reading mp3 files
mp4	Support for MP4 container format
mpeg	Adds libmpeg3 support to various packages
mpi	Adds MPI (Message Passing Interface) layer to the apps that support it
mplayer	Enable mplayer support for playback or encoding
msn	Enable MSN Messenger IM protocol support
msql	Adds support for the MSQL database server
mssql	Adds support for Microsoft SQL Server database
mtp	Enable support for Media Transfer Protocol
mule	Adds multi-language support to XEmacs
multilib	On 64bit systems, if you want to be able to compile 32bit and 64bit binaries
musepack	Enable support for the musepack audio codec
musicbrainz	Lookup audio metadata using MusicBrainz community service (musicbrainz.org)
mysql	Adds mySQL Database support
mysqli	Adds support for the improved mySQL libraries
nas	Adds support for network audio sound
ncurses	Adds ncurses support (console display library)
neXt	Enable neXt toolkit
neon	Enable optimization support for ARM NEON processors
netboot	Enables network booting
netcdf	Enable NetCDF data format support
networkmanager	Enable net-misc/networkmanager support
nis	Support for NIS/YP services
nls	Adds Native Language Support (using gettext - GNU locale utilities)
nntp	Add support for newsgroups (Network News Transfer Protocol)
nocd	Install all files required to run the application without a CD mounted
nocxx	Old flag -- USE=cxx from now on
nptl	Enable support for Native POSIX Threads Library, the new threading module (requires linux-2.6 or better usually)
nsplugin	Build plugin for browsers supporting the Netscape plugin architecture (that is almost any modern browser)
ocaml	Adds support/bindings for the Ocaml language
ocamlopt	Enables ocamlopt support (ocaml native code compiler) -- Produces faster programs (Warning: you have to disable/enable it at a global scale)
oci8	Adds Oracle 8 Database Support
oci8-instant-client	Use dev-db/oracle-instantclient-basic as Oracle provider instead of requiring a full Oracle server install
odbc	Adds ODBC Support (Open DataBase Connectivity)
offensive	Enables potentially offensive items in packages
ofx	Enable support for importing (and exporting) OFX (Open Financial eXchange) data files
ogg	Adds support for the Ogg container format (commonly used by Vorbis, Theora and flac)
old-linux	Add support for linux-2.4 and older
openal	Adds support for the Open Audio Library
openexr	Support for the OpenEXR graphics file format
opengl	Adds support for OpenGL (3D graphics)
openmp	Build support for the OpenMP (support parallel computing), requires >=sys-devel/gcc-4.2 built with USE="openmp"
oracle	Enable Oracle Database support
osc	Enables support for Open Sound Control
oscar	Enable Oscar (AIM/ICQ) IM protocol support
oss	Adds support for OSS (Open Sound System)
pam	Adds support for PAM (Pluggable Authentication Modules) - DANGEROUS to arbitrarily flip
pch	Enable precompiled header support for faster compilation at the expense of disk space and memory (>=sys-devel/gcc-3.4 only)
pcmcia	Adds support for PCMCIA slots/devices found on laptop computers
pcntl	Adds support for process creation functions
pcre	Adds support for Perl Compatible Regular Expressions
pda	Adds support for portable devices
pdf	Adds general support for PDF (Portable Document Format), this replaces the pdflib and cpdflib flags
perl	Adds optional support/bindings for the Perl language
php	Include support for the PHP language
plasma	Build optional plasma widgets that require kde-base/libplasma
plotutils	Add support for plotutils (library for 2-D vector graphics)
png	Adds support for libpng (PNG images)
policykit	Enable PolicyKit authentication support
portaudio	Adds support for the crossplatform portaudio audio API
posix	Adds support for POSIX-compatible functions
postgres	Adds support for the postgresql database
ppds	Adds support for automatically generated ppd (printing driver) files
prefix	Defines if a Gentoo Prefix offset installation is used
prelude	Adds support/bindings for the Prelude Intrusion Detection System
profile	Adds support for software performance analysis (will likely vary from ebuild to ebuild)
pulseaudio	Adds support for PulseAudio sound server
python	Adds optional support/bindings for the Python language
qdbm	Adds support for the qdbm (Quick Database Manager) library
qmail-spp	Adds support for qmail SMTP plugins
qt4	Adds support for the Qt GUI/Application Toolkit version 4.x
quicktime	Adds support for OpenQuickTime
radius	Adds support for RADIUS authentication
raw	Add support for raw image formats
rdesktop	Adds support for the remote desktop protocol, usually used to connect to Windows servers
readline	Enables support for libreadline, a GNU line-editing library that almost everyone wants
recode	Enables support for the GNU recode library
rss	Enables support for RSS feeds
ruby	Adds support/bindings for the Ruby language
samba	Adds support for SAMBA (Windows File and Printer sharing)
sasl	Adds support for the Simple Authentication and Security Layer
savedconfig	Use this to restore your config from /etc/portage/savedconfig ${CATEGORY}/${PN}. Make sure your USE flags allow for appropriate dependencies
scanner	Adds support for scanner hardware (e.g. build the sane frontend in kdegraphics)
sdl	Adds support for Simple Direct Layer (media library)
seamonkey	Adds support for the Seamonkey web-browser
selinux	!!internal use only!! Security Enhanced Linux support, this must be set by the selinux profile or breakage will occur
semantic-desktop	Cross-KDE support for semantic search and information retrieval
session	Adds persistent session support
sharedmem	Adds support for shared memory use
shorten	Adds support for the shorten audio compressor
simplexml	support for SimpleXML
skey	Enable S/Key (Single use password) authentication support
slang	Adds support for the slang text display library (it's like ncurses, but different)
slp	Adds Service Locator Protocol support
smartcard	Enables smartcard support
smp	Enable support for multiprocessors or multicore systems
sndfile	Adds support for libsndfile
snmp	Adds support for the Simple Network Management Protocol if available
soap	Adds support for SOAP (Simple Object Access Protocol)
sockets	Adds support for tcp/ip sockets
socks5	Adds support for the socks5 proxy
sound	Enable sound support
source	Zip the sources and install them
sox	Adds support for Sound eXchange (SoX)
speex	Adds support for the speex audio codec (used for speech)
spell	Adds dictionary support
sqlite	Adds support for sqlite - embedded sql database
sqlite3	Adds support for sqlite3 - embedded sql database
sse	fast floating point optimization for PentiumIII+ class chips
sse2	faster floating point optimization for SSE2 capable chips
ssl	Adds support for Secure Socket Layer connections
startup-notification	Enable application startup event feedback mechanism
static	!!do not set this during bootstrap!! Causes binaries to be statically linked instead of dynamically
static-libs	Build static libraries
subversion	Enable subversion (version control system) support
suid	Enable setuid root program, with potential security risks
svg	Adds support for SVG (Scalable Vector Graphics)
svga	Adds support for SVGAlib (graphics library)
sybase	Adds support for the Sybase SQL Database Server
sybase-ct	Adds support for Sybase-CT
symlink	Force kernel ebuilds to automatically update the /usr/src/linux symlink
syslog	Enables support for syslog
sysvipc	Support for System V-compatible inter-process communication
szip	Use the szip compression library
taglib	Enable tagging support with taglib
tcl	Adds support the Tcl language
tcmalloc	Use the dev-util/google-perftools libraries to replace the malloc() implementation with a possibly faster one
tcpd	Adds support for TCP wrappers
test	Workaround to pull in packages needed to run with FEATURES=test. Portage-2.1.2 handles this internally, so don't set it in make.conf/package.use anymore
theora	Adds support for the Theora Video Compression Codec
threads	Adds threads support for various packages. Usually pthreads
tidy	Adds support for HTML Tidy
tiff	Adds support for the TIFF image format
timidity	Build with Timidity++ (MIDI sequencer) support
tk	Adds support for Tk GUI toolkit
tokenizer	Adds support for the PHP file parser
truetype	Adds support for FreeType and/or FreeType2 fonts
uclibc	Enable uclibc specific patches and build or link uclibc
udev	Enable sys-fs/udev integration (device discovery, power and storage device support, etc)
unicode	Adds support for Unicode
usb	Adds USB support to applications that have optional USB support (e.g. cups)
v4l	Enable support for video4linux (using linux-headers or userspace libv4l libraries)
vanilla	Do not add extra patches which change default behaviour; DO NOT USE THIS ON A GLOBAL SCALE as the severity of the meaning changes drastically
vcd	Video CD support
vhosts	Adds support for installing web-based applications into a virtual-hosting environment
videos	Install optional video files (used in some games)
vim-syntax	Pulls in related vim syntax scripts
vnc	Enable VNC (remote desktop viewer) support
vorbis	Adds support for the OggVorbis audio codec
wavpack	Add support for wavpack audio compression tools
wddx	Adds support for Web Distributed Data eXchange
wifi	Enable wireless network functions
win32codecs	use win32codecs package for dll avi decoding support (wmv and what not)
wmf	Adds support for the Windows Metafile vector image format
wxwidgets	Adds support for wxWidgets/wxGTK GUI toolkit
x264	Enable h264 encoding using x264
xattr	Adds support for extended attributes (filesystem-stored metadata)
xcb	Support the X C-language Binding, a replacement for Xlib
xcomposite	Enable support for the Xorg composite extension
xemacs	Add support for XEmacs
xface	Adds xface support used to allow a small image of xface format to be included in an email via the header 'X-Face'
xft	Build with support for XFT font renderer (x11-libs/libXft)
xine	Add support for the XINE movie libraries
xinerama	Add support for the xinerama X11 extension, which is mandatory if you work in multiple monitors setup
xinetd	Add support for the xinetd super-server
xml	Add support for XML files
xmlrpc	Support for xml-rpc library
xmp	Enable support for Extensible Metadata Platform (Adobe XMP)
xmpp	Enable support for Extensible Messaging and Presence Protocol (XMPP) formerly known as Jabber
xosd	Sends display using the X On Screen Display library
xpm	Adds support for XPM graphics format
xscreensaver	Adds support for XScreenSaver extension
xsl	Check/Support flag for XSL library (version 1)
xulrunner	Build native browser integration against xulrunner instead of firefox or seamonkey
xv	Adds in optional support for the Xvideo extension (an X API for video playback)
xvid	Adds support for xvid.org's open-source mpeg-4 codec
yahoo	Enable Yahoo Messenger IM protocol support
yaz	Adds in optional support for the Z39.50 Protocol for Information Retrieval (YAZ)
zeroconf	Support for DNS Service Discovery (DNS-SD)
zlib	Adds support for zlib (de)compression
zsh-completion	Enable zsh completion support

2. Local Use Flags

Categories

app-accessibility	app-admin	app-antivirus	app-arch	app-backup	app-benchmarks
app-cdr	app-crypt	app-dicts	app-doc	app-editors	app-emacs
app-emulation	app-forensics	app-i18n	app-laptop	app-misc	app-mobilephone
app-office	app-pda	app-portage	app-shells	app-text	app-vim
dev-cpp	dev-db	dev-embedded	dev-games	dev-haskell	dev-java
dev-lang	dev-libs	dev-lisp	dev-lua	dev-ml	dev-perl
dev-php	dev-python	dev-ruby	dev-scheme	dev-tcltk	dev-tex
dev-util	dev-vcs	games-action	games-arcade	games-board	games-emulation
games-engines	games-fps	games-kids	games-misc	games-mud	games-puzzle
games-roguelike	games-rpg	games-simulation	games-sports	games-strategy	games-util
gnome-base	gnome-extra	gnustep-apps	gnustep-base	gpe-base	kde-base
kde-misc	lxde-base	mail-client	mail-filter	mail-mta	media-fonts
media-gfx	media-libs	media-plugins	media-radio	media-sound	media-tv
media-video	net-analyzer	net-dialup	net-dns	net-firewall	net-fs
net-ftp	net-im	net-irc	net-libs	net-mail	net-misc
net-nds	net-news	net-nntp	net-p2p	net-print	net-proxy
net-voip	net-wireless	rox-base	rox-extra	sci-astronomy	sci-biology
sci-chemistry	sci-electronics	sci-geosciences	sci-libs	sci-mathematics	sci-misc
sci-physics	sci-visualization	sec-policy	sys-apps	sys-auth	sys-block
sys-boot	sys-cluster	sys-devel	sys-freebsd	sys-fs	sys-infiniband
sys-kernel	sys-libs	sys-power	sys-process	virtual	www-apache
www-apps	www-client	www-misc	www-plugins	www-servers	x11-apps
x11-base	x11-drivers	x11-libs	x11-misc	x11-plugins	x11-terms
x11-themes	x11-wm	xfce-base	xfce-extra

app-accessibility

Package	Flag	Description
at-spi2-core	introspection	Use dev-libs/gobject-introspection for introspection
brltty	api	build brltty's application program interface
	beeper	support the console tone generator
	contracted-braille	support in-line contracted braille
	fm	support for the sound card synthesizer
	learn-mode	support for interactive command learn mode
	midi	support the musical instrument digital interface
	pcm	support for sound card digital audio
	speech	speech support
eflite	16k_voice	Use a higher-quality voice.
emacspeak	espeak	Adds support for the espeak tts engine
festival	mbrola	Adds support for mbrola voices
festival-it	mbrola	Adds support for mbrola voices
freetts	jsapi	build Java Speech API (JSAPI)
freetts	mbrola	Adds support for mbrola voices
gnome-speech	espeak	Adds support for the espeak speech driver (default)
	festival	Adds support for the festival speech driver
	freetts	Adds support for the freetts speech driver
speech-dispatcher	espeak	Adds support for espeak speech engine
speech-dispatcher	flite	Adds support for flite speech engine
speechd-el	brltty	brltty support

app-admin

Package	Flag	Description
bcfg2	server	Installs scripts to be used on the server-side of this app
collectd	collectd_plugins_apache	Build the apache input plugin (transferred bytes, handled requests, detailed scoreboard statistics)
	collectd_plugins_apcups	Build the apcups input plugin (UPS charge, load, input/output/battery voltage, etc.)
	collectd_plugins_ascent	Build the ascent input plugin (statistics about a free server for World of Warcraft)
	collectd_plugins_battery	Build the battery input plugin (charge, current and voltage of ACPI and PMU based laptop batteries)
	collectd_plugins_bind	Build the bind input plugin (name server and resolver statistics)
	collectd_plugins_conntrack	Build the conntrack input plugin (number of nf_conntrack entries)
	collectd_plugins_contextswitch	Build the contextswitch input plugin (number of context switches done by the operating system)
	collectd_plugins_cpu	Build the cpu input plugin (time spent in the system, user, nice, idle, and related states)
	collectd_plugins_cpufreq	Build the cpufreq input plugin (CPU frequency, for laptops with speedstep or similar)
	collectd_plugins_csv	Build the csv output plugin (write to comma separated values (CSV) files)
	collectd_plugins_curl	Build the curl input plugin (parse statistics from websites using regular expressions)
	collectd_plugins_curl_json	Build the curl_json input plugin (get json data via curl and parse it)
	collectd_plugins_curl_xml	Build the curl_xml input plugin (get xml data via curl and parse it)
	collectd_plugins_dbi	Build the dbi input plugin (execute SQL statements on databases and interpret the reply)
	collectd_plugins_df	Build the df input plugin (mountpoint usage)
	collectd_plugins_disk	Build the disk input plugin (sectors read/written, number of read/write actions, average completion time of IO-operations)
	collectd_plugins_dns	Build the dns input plugin (collects statistics of your DNS traffic on port udp/53)
	collectd_plugins_email	Build the email input plugin (opens a UNIX domain socket and starts accepting connections on that socket)
	collectd_plugins_entropy	Build the entropy input plugin (available entropy on a system)
	collectd_plugins_exec	Build the exec input/output plugin (executes scripts / applications and reads values back)
	collectd_plugins_filecount	Build the filecount input plugin (countd the number of files in a directory and all its subdirectories)
	collectd_plugins_fscache	Build the fscache input plugin (information about the caching infrastructure for network file-systems etc)
	collectd_plugins_gmond	Build the gmond input plugin (receive data from gmond, the client daemon of the Ganglia project)
	collectd_plugins_hddtemp	Build the hddtemp input plugin (temperature of hard disks)
	collectd_plugins_interface	Build the interface input plugin (information about traffic, packets and errors of interfaces)
	collectd_plugins_ipmi	Build the ipmi input plugin (read hardware sensors from servers using the Intelligent Platform Management Interface (IPMI))
	collectd_plugins_iptables	Build the iptables input plugin (statistics from a ip_tables based packet filter)
	collectd_plugins_irq	Build the irq input plugin (number of times each interrupt has been handled by the os)
	collectd_plugins_java	Build the java input plugin (embeds a JVM into collectd for writing plugins)
	collectd_plugins_libvirt	Build the libvirt input plugin (statistics about virtualized guests on a system)
	collectd_plugins_load	Build the load input plugin (system load)
	collectd_plugins_logfile	Build the logfile output plugin (writes log messages to a text file)
	collectd_plugins_madwifi	Build the madwifi input plugin (information about Atheros wireless LAN chipsets)
	collectd_plugins_match_empty_counter	Build the match_empty_counter filter plugin
	collectd_plugins_match_hashed	Build the match_hashed filter plugin
	collectd_plugins_match_regex	Build the match_regex filter plugin
	collectd_plugins_match_timediff	Build the match_timediff filter plugin
	collectd_plugins_match_value	Build the match_value filter plugin
	collectd_plugins_mbmon	Build the mbmon input plugin (information from mainboard sensors)
	collectd_plugins_memcachec	Build the memcachec input plugin (connects to a memcached server)
	collectd_plugins_memcached	Build the memcached input plugin (connects to a memcached daemon)
	collectd_plugins_memory	Build the memory input plugin (physical memory utilization)
	collectd_plugins_multimeter	Build the multimeter input plugin (reads a voltage or current from a multimeter connected to a serial bus)
	collectd_plugins_mysql	Build the mysql input plugin (connects to an MySQL-database and issues a SHOW STATUS command)
	collectd_plugins_netlink	Build the netlink input plugin (opens a netlink socket to the Linux kernel for getting statistics)
	collectd_plugins_network	Build the network input/output plugin (communicates with other instances of collectd)
	collectd_plugins_nfs	Build the nfs input plugin (usage of the Network File System)
	collectd_plugins_nginx	Build the nginx input plugin (number of requests handled by the nginx daemon)
	collectd_plugins_notify_desktop	Build the notify_desktop output plugin (uses libnotify to display notifications to the user)
	collectd_plugins_notify_email	Build the notify_email output plugin (uses libESMTP to send notifications to a configured email address)
	collectd_plugins_ntpd	Build the ntpd input plugin (queries an NTP server)
	collectd_plugins_nut	Build the nut input plugin (collects UPS statistics using the Network UPS Tools)
	collectd_plugins_olsrd	Build the olsrd input plugin (reads information about the Optimized Link State Routing daemon)
	collectd_plugins_onewire	Build the onewire input plugin (collects temperature information from sensors)
	collectd_plugins_openvpn	Build the openvpn input plugin (reads the status file printed by OpenVPN)
	collectd_plugins_oracle	Build the oracle input plugin (SQL-queries one or more Oracle database systems)
	collectd_plugins_perl	Build the perl language binding plugin (embeds a Perl interpreter into collectd for writing plugins)
	collectd_plugins_ping	Build the ping input plugin (measures network latency)
	collectd_plugins_postgresql	Build the postgresql input plugin (connects to and executes SQL statements on a PostgreSQL database)
	collectd_plugins_powerdns	Build the powerdns input plugin (connects to a local PowerDNS instance)
	collectd_plugins_processes	Build the processes input plugin (statistics about processes)
	collectd_plugins_protocols	Build the protocols input plugin (network protocols)
	collectd_plugins_python	Build the python language binding plugin (embeds a Python interpreter into collectd for writing plugins)
	collectd_plugins_rrdcached	Build the rrdcached input/output plugin (connects to rrdcached and submits updates for RRD files)
collectd_plugins_rrdtool	Build the rrdtool output plugin (writes values to RRD-files)
collectd_plugins_sensors	Build the sensors input plugin (uses lm-sensors to read hardware sensors)
collectd_plugins_serial	Build the serial input plugin (collects the traffic on serial interfaces)
collectd_plugins_snmp	Build the snmp input plugin (read values from network devices using SNMP)
collectd_plugins_swap	Build the swap input plugin (amount of memory currently written to swap)
collectd_plugins_syslog	Build the syslog output plugin (receives messages from collectd and dispatches them to syslog)
collectd_plugins_table	Build the table input plugin (parses table-like structured plain text)
collectd_plugins_tail	Build the tail input plugin (follows logfiles as e.g. tail -f)
collectd_plugins_target_notification	Build the target_notification filter plugin
collectd_plugins_target_replace	Build the target_replace filter plugin
collectd_plugins_target_scale	Build the target_scale filter plugin
collectd_plugins_target_set	Build the target_set filter plugin
collectd_plugins_tcpconns	Build the tcpconns input plugin (number of TCP connections to or from a specified port)
collectd_plugins_teamspeak2	Build the teamspeak2 input plugin (collects traffic statistics from a teamspeak2 instance)
collectd_plugins_ted	Build the ted input plugin (connects to The Energy Detective and reads the current power over connected power lines)
collectd_plugins_thermal	Build the thermal input plugin (ACPI thermal zone information)
collectd_plugins_tokyotyrant	Build the tokyotyrant input plugin (number of records and file size from a running Tokyo Tyrant server)
collectd_plugins_unixsock	Build the unixsock output plugin (opens a UNIX domain socket and accepts connections)
collectd_plugins_uptime	Build the uptime input plugin (system uptime)
collectd_plugins_users	Build the users input plugin (number of users currently logged in)
collectd_plugins_uuid	Build the uuid plugin (tries hard to determine the UUID of the system it is running on)
collectd_plugins_varnish	Build the varnish input plugin
collectd_plugins_vmem	Build the vmem input plugin (information about the virtual memory subsystem)
collectd_plugins_vserver	Build the vserver input plugin (virtual servers running on a system)
collectd_plugins_wireless	Build the wireless input plugin (signal quality, signal power and signal-to-noise ratio for wireless LAN cards)
collectd_plugins_write_http	Build the write_http output plugin (sends the values collected by collectd to a web-server)
contrib	Install user-contributed files in the doc directory
conky	apcupsd	enable support for sys-power/apcupsd
	audacious	enable monitoring of music played by media-sound/audacious
	eve	enable support for the eve-online skill monitor
	iostats	enable support for per-task I/O statistics
	lua	enable if you want Lua scripting support
	lua-cairo	enable if you want Lua Cairo bindings for Conky (also enables lua support)
	lua-imlib	enable if you want Lua Imlib2 bindings for Conky (also enables lua and imlib support)
	math	enable support for glibc's libm math library
	moc	enable monitoring of music played by media-sound/moc
	mpd	enable monitoring of music controlled by media-sound/mpd
	nano-syntax	enable syntax highlighting for app-editors/nano
	nvidia	enable reading of nvidia card temperature sensors via media-video/nvidia-settings
	portmon	enable support for tcp (ip4) port monitoring
	thinkpad	enable support for IBM/Lenovo notebooks
	weather-metar	enable support for metar weather service
	weather-xoap	enable support for metar and xoap weather service
	xmms2	enable monitoring of music played by media-sound/xmms2
diradm	automount	Support for automount data in LDAP
diradm	irixpasswd	Support for storing separate IRIX passwords
gkrellm	X	Build both the X11 gui (gkrellm) and the server (gkrellmd). Disabling this flag builds the server only.
	gnutls	Enable SSL support for mail checking with net-libs/gnutls (overrides 'ssl' USE flag)
	hddtemp	Enable monitoring harddrive temperatures via app-admin/hddtemp
	lm_sensors	Enable monitoring sensors via sys-apps/lm_sensors
	ntlm	Enable NTLM authentication for mail checking with net-libs/libntlm
	ssl	Enable SSL support for mail checking with dev-libs/openssl
gnome-system-tools	nfs	Adds support for NFS shares
hddtemp	network-cron	Monthly cronjob to update hddtemp.db.
lcap	lids	If you have the Linux Intrusion Detection System
mcollective	client	Install client utilities
packagekit-base	connman	Add support for net-misc/connman
	cron	Install cron script for auto-update
	entropy	Enable Entropy backend
	introspection	Use dev-libs/gobject-introspection Enable introspection
	pm-utils	Add pm-utils (suspend/resume) functionalities
	static-libs	Compile static archives
	udev	Add support for sys-fs/udev
prelude-manager	tcpwrapper	Add support for tcp_wrappers
puppet	augeas	Enable augeas support
	diff	Enable diff support
	rrdtool	Enable rrdtool support
	shadow	Enable shadow support
rsyslog	extras	Add support for the UDP spoofing module (omudpspoof) using net-libs/libnet
	relp	Add support for the Reliable Event Logging Protocol using dev-libs/librelp
	zeromq	Add support for the ZeroMQ input and output plugins using net-libs/zeromq
sagan	libdnet	Add support for dev-libs/libdnet
	lognorm	Add support for log/rules normalizations via dev-libs/liblognorm
	pcap	Add support for network packet capture via net-libs/libpcap
	smtp	Build witch SMTP (E-Mail) support
sshguard	ipfilter	Enable ipfilter firewall support (only for *bsd)
sudo	offensive	Let sudo print insults when the user types the wrong password.
syslog-ng	json	Enable support for JSON template formatting via dev-libs/json-glib
	mongodb	Enable support for mongodb destinations
	spoof-source	Enable support for spoofed source addresses
	sql	Enable support for SQL destinations
sysstat	cron	Install /etc/cron.d script to periodically run sar
sysstat	isag	Install isag, the Interactive System Activity Graph tool
testdisk	ntfs	Include the ability to read NTFS filesystems
testdisk	reiserfs	include reiserfs reading ability
ulogd	mysql	Build MYSQL output plugin to save packets in a mysql database.
	pcap	Build PCAP output plugin to save packets in PCAP format. Uses the net-libs/libpcap library
	postgres	Build PGSQL output plugin to save packets in a postgres database.
	sqlite	Build SQLITE3 output plugin to save packets in an sqlite database.
webalizer	xtended	Include the 404 extension

app-antivirus

Package	Flag	Description
clamav	clamdtop	A Top like tool which shows what clamd is currently scanning amongst other things

app-arch

Package	Flag	Description
cabextract	extra-tools	Install experimental tools: wince_info and wince_rename for examining and processing Windows CE installation cabinet header files; cabinfo for examining the structure of a cab file.
cfv	bittorrent	Enable support for checking .torrent files
dpkg	dselect	Build the dselect package-management frontend
dump	ermt	encrypted rmt support
file-roller	nautilus	Enable file-roller to integrate with gnome-base/nautilus by providing entries in its context menu
file-roller	packagekit	Enable support for the distro-neutral package manager GUI app-admin/packagekit
gzip	pic	disable optimized assembly code that is not PIC friendly
libarchive	bzip2	Allow accessing bzip2-compressed archives through libbz2 (which comes with app-arch/bzip2). This only affects libarchive's native support: bsdtar will keep using bunzip2 as a filter if that's not built-in.
	e2fsprogs	Use file flags from sys-fs/e2fsprogs headers instead of virtual/os-headers headers
	nettle	Use dev-libs/nettle as crypto backend
	static	Build bsdtar and bsdcpio as static archives, removing dependencies over the enabled compression libraries (lzma, libbz2, zlib).
	zlib	Allow accessing gzip-compressed archives through sys-libs/zlib. This only affects libarchive's native support: bsdtar will keep using gunzip as a filter if that's not built-in. It's also needed for supporting extraction of ZIP files.
p7zip	rar	Enable support for non-free rar decoder
pbzip2	symlink	Install symlinks which override app-arch/bzip2 implementation
rar	all_sfx	Install all SFX (Self-Extracting) files rather than just the native format (allows creation of Windows EXEs on Linux ELF systems)
rpm	magic	Add magic file support (sys-apps/file)
rpm	webdav-neon	Include support for net-libs/neon
unzip	natspec	Use dev-libs/libnatspec to correctly decode non-ascii file names archived in Windows.
zip	natspec	Use dev-libs/libnatspec to correctly decode non-ascii file names archived in Windows.

app-backup

Package	Flag	Description
amanda	devpay	Support for using Amazon DevPay with S3
	s3	Support for backing up to the Amazon S3 system
	xfs	Support for backing up raw XFS filesystems using xfsdump
backup-manager	s3	Support for backing up to the Amazon S3 system
bacula	bacula-clientonly	Disable DB support, and just build a client
	bacula-nodir	Disable building of director
	bacula-nosd	Disable building of storage daemon
	logwatch	Install support files for logwatch
boxbackup	client-only	Disable server support, and just build a client
dar	dar32	Enables --enable-mode=32 option, which replace infinite by 32 bit integers
	dar64	Enables --enable-mode=64 option, which replace infinite by 64 bit integers
	gcrypt	Enables strong encryption support
deja-dup	nautilus	Build gnome-base/nautilus extension
duplicity	s3	Support for backing up to the Amazon S3 system
spideroak-bin	headless	Build without graphic frontend
	pycurl-bundled	Use bundled pycurl
	qt-bundled	Use bundled Qt4 libraries
	system-libs	Use the system libraries rather than bundled
tsm	hsm	Installs Tivoli Storage Manager for Space Management

app-benchmarks

Package	Flag	Description
bootchart	acct	Enable process accounting
jmeter	beanshell	Enable BeanShell scripting support
sysbench	aio	Enable libaio support

app-cdr

Package	Flag	Description
backlite	mplayer	Add support for mplayer preview in addition to X11 and phonon
brasero	introspection	Use dev-libs/gobject-introspection for introspection
	libburn	Enable dev-libs/libburn backend
	nautilus	Build the gnome-base/nautilus extension
	packagekit	Enable support for the distro-neutral package manager GUI app-admin/packagekit
	playlist	Enable support for playlists through dev-libs/totem-pl-parser
	tracker	Enable audio playlist search using the app-misc/tracker indexer
cdemu	cdemud	Pull app-cdr/cdemud dependency, useful in chroot environment (bug #315491). Do not disable until you know what you are doing.
cdrdao	gcdmaster	Enable building of gcdmaster application
cdrdao	pccts	Use dev-util/pccts instead of the built-in substitution
cdrkit	hfs	Provide building of HFS (Apple) CD-images
cuetools	extras	Install additional script that tag files based on cue/toc file information
disc-cover	cdrom	Enable audio CD support. This is not needed to make www-apps/disc-cover work.
gaffitter	scripts	Install additional gaffitter scripts for external programs
k3b	emovix	Enable burning support for eMoviX images
k3b	wav	Enable support for reading WAVE files
mirage2iso	pinentry	Support app-crypt/pinentry password input backend.
mybashburn	normalize	Add support for normalizing audio file volume levels

app-crypt

Package	Flag	Description
ccid	twinserial	Enable twinserial reader
ekeyd	minimal	Only install the ekey-egd-linux service rather than the full ekeyd package.
	munin	Install a plugin for net-analyzer/munin to graph statistical data from ekeyd.
	usb	Build the libusb-based userland daemon for accessing the EntropyKey (alternative to the CDC USB driver). It is suggested to use this option by default, as the CDC driver in the kernel often seems to be fragile (or the gadget implementation on the EntropyKey is too buggy), and can cause various problems.
gnupg	idea	Use the patented IDEA algorithm
	openct	Bring in dev-libs/openct as a dependency; enable scdaemon.
	pcsc-lite	Bring in sys-apps/pcsc-lite as a dependency; enable scdaemon.
	smartcard	Build scdaemon software. Enables usage of OpenPGP cards. For other type of smartcards, try app-crypt/gnupg-pkcs11-scd.
	usb	Build direct CCID access for scdaemon; requires dev-libs/libusb.
gpgme	common-lisp	Install common-lisp files
gpgme	pth	Enable support for GNU Portable Threads multithreading library
heimdal	hdb-ldap	Adds support for LDAP as a database backend
	otp	Adds support for one-time passwords
	pkinit	Adds support for PKINIT for the initial ticket
kstart	afs	Enables afs support which means you can acquire an afs token and set PAGs. It's recommended to set this USE if you need authenticated access to an AFS cell for your daemon/app.
mit-krb5	doc	Creates and installs the API and implementation documentation. This is only useful if you want to develop software which depends on kerberos.
	keyutils	Enable for the keyring ccache using keyutils.
	openldap	Enable support for ldap as a database backend.
	pkinit	Enable pkinit support for the initial ticket.
ophcrack	tables	Require the additional tables used to carry out cracking (app-crypt/ophcrack-tables)
ophcrack-tables	vistafree	Installs the free Vista ophcrack tables
	xpfast	Installs the fast XP ophcrack tables
	xpsmall	Installs the small free XP ophcrack tables
seahorse	introspection	Use dev-libs/gobject-introspection for introspection
seahorse	ldap	Enable seahorse to manipulate GPG keys on a LDAP server.
seahorse-plugins	applet	Enable seahorse applet for gnome-base/gnome-panel
	gedit	Enable text encryption plugin to integrate into app-editors/gedit
	nautilus	Enable file encryption plugin to integrate into the gnome-base/nautilus context menu
tpm-tools	pkcs11	Build Token data management utilities based on OpenCryptoki's (dev-libs/opencryptoki) PKCS#11 implementation.

app-dicts

Package	Flag	Description
aspell-be	classic	Support classic spelling by default
gwaei	unique	Enable single instance support using dev-libs/libunique.

app-doc

Package	Flag	Description
doxygen	nodot	removes graphviz dependency, along with dot graphs
doxygen	tcl	adds experimental support for parsing/documenting Tcl source code
linuxfromscratch	htmlsingle	Also install single-page HTML version
pms	html	Generate PMS as .html as well
tldp-howto	html	Install the docs in multipage HTML format (default)
	htmlsingle	Install the docs in single page HTML format
	pdf	Install the docs in pdf format
	text	Install the docs in plain text format

app-editors

Package	Flag	Description
bluefish	gtk3	Enable gtk3 frontend instead of gtk2 one
cssed	plugins	Install plugin development files
emacs	athena	Enable the MIT Athena widget set (x11-libs/libXaw)
	gconf	Use gnome-base/gconf to read the system font name
	gzip-el	Compress bundled Emacs Lisp source
	hesiod	Enable support for net-dns/hesiod
	leim	Add support for Emacs input methods
	sendmail	Build Emacs with MTA support
	toolkit-scroll-bars	Use the selected toolkit's scrollbars in preference to Emacs' own scrollbars
emacs-vcs	athena	Enable the MIT Athena widget set (x11-libs/libXaw)
	gconf	Use gnome-base/gconf to read the system font name
	gsettings	Use gsettings (dev-libs/glib) to read the system font name
	gtk3	Link against version 3 of the GIMP Toolkit instead of version 2 (x11-libs/gtk+)
	gzip-el	Compress bundled Emacs Lisp source
	hesiod	Enable support for net-dns/hesiod
	imagemagick	Use media-gfx/imagemagick for image processing
	libxml2	Use dev-libs/libxml2 to parse XML instead of the internal Lisp implementations
	toolkit-scroll-bars	Use the selected toolkit's scrollbars in preference to Emacs' own scrollbars
	wide-int	Prefer wide Emacs integers (typically 62-bit). This option has an effect only on architectures where "long" and "long long" types have different size.
fe	sendmail	Send mail after editor abend
gedit	introspection	Use dev-libs/gobject-introspection for introspection
gedit-plugins	charmap	Insert special characters just by clicking on them
	synctex	Synchronize between LaTeX and PDF with gedit and evince
	terminal	Embed a terminal in the bottom pane
gvim	netbeans	Include netbeans externaleditor integration support
jasspa-microemacs	nanoemacs	Build NanoEmacs instead of MicroEmacs
joe	xterm	Enable full xterm clipboard support
latexila	latexmk	Install dev-tex/latexmk (used by default for the build tools)
latexila	rubber	Install dev-tex/rubber (can be used for the build tools)
leafpad	emacs	Enable Emacs key theme
nano	debug	Enable debug messages and assert warnings. Note that these will all be sent straight to stderr rather than some logging facility.
	justify	Enable justify/unjustify functions for text formatting.
	minimal	Disable all fancy features, including ones that otherwise have a dedicated USE flag (such as spelling).
tea	aspell	Enable spell checking using aspell
	enchant	Enable spell checking using enchant
	hacking	Enable hacking support
	hunspell	Enable spellchecking using hunspell
vim	X	Link console vim against X11 libraries to enable title and clipboard features in xterm
vim	vim-pager	Install vimpager and vimmanpager links
xemacs	athena	Chooses the MIT Athena widget set
	dnd	Enables support for the x11-libs/dnd drag-n-drop library
	eolconv	Support detection and translation of newline conventions
	pop	Support POP for mail retrieval
	xim	Enable X11 XiM input method
xmlcopyeditor	guidexml	Install GuideXML templates to work with Gentoo official docs
zile	valgrind	Enable usage of dev-util/valgrind in tests

app-emacs

Package	Flag	Description
anything	extensions	Install optional extensions
auctex	preview-latex	Use bundled preview-latex
bbdb	tex	Install plain TeX support files
calfw	howm	Add support for the app-emacs/howm note-taking tool
company-mode	ropemacs	Install backend for dev-python/ropemacs
company-mode	semantic	Install backend for semantic (app-emacs/cedet)
delicious	planner	Include support for app-emacs/planner
emacs-common-gentoo	emacs22icons	Install Emacs 22 style icons
emhacks	jde	Enable support for Java Development Environment
org-mode	contrib	Install user-contributed files
remember	bbdb	Include support for app-emacs/bbdb
remember	planner	Include support for app-emacs/planner
slime	xref	Install xref.lisp cross-referencing tool
vm	bbdb	Include support for app-emacs/bbdb
wanderlust	bbdb	Include support for app-emacs/bbdb
wikipedia-mode	outline-magic	Enable support for outline-mode extensions (app-emacs/outline-magic)

app-emulation

Package	Flag	Description
aqemu	kvm	Add kernel virtual machine support
bochs	debugger	Enable the bochs debugger
e-uae	capslib	Add CAPS library support
e-uae	sdl-sound	Use media-libs/sdl-sound for audio output
emul-linux-x86-baselibs	development	Install pkgconfig files
emul-linux-x86-compat	development	Install pkgconfig files
emul-linux-x86-cpplibs	development	Install pkgconfig files
emul-linux-x86-db	development	Install pkgconfig files
emul-linux-x86-gstplugins	development	Install pkgconfig files
emul-linux-x86-gtklibs	development	Install pkgconfig files
emul-linux-x86-gtkmmlibs	development	Install pkgconfig files
emul-linux-x86-medialibs	development	Install pkgconfig files
emul-linux-x86-motif	development	Install pkgconfig files
emul-linux-x86-opengl	development	Install pkgconfig files
emul-linux-x86-qtlibs	development	Install pkgconfig files
emul-linux-x86-sdl	development	Install pkgconfig files
emul-linux-x86-soundlibs	development	Install pkgconfig files
emul-linux-x86-xlibs	development	Install pkgconfig files
fuse-utils	gcrypt	Use dev-libs/libgcrypt for low-level crypto of some features, including logfiles.
ganeti	drbd	Enable DRBD support
	filestorage	Enable File Storage
	htools	Enable htools support
	kvm	Enable KVM support
	lxc	Enable Linux Countainers support
	sharedstorage	Enable Shared Storage support
	xen	Enable Xen support
lib765	libdsk	Enable support for the floppy disk emulation library app-emulation/libdsk
libguestfs	fuse	Enable image mount support via fuse
	haskell	Install GHC binding
	javadoc	Install java docs
libspectrum	gcrypt	Use dev-libs/libgcrypt for low-level crypto of some features, including logfiles.
libvirt	iscsi	Allow using an iSCSI remote storage server as pool for disk image storage
	json	Support QEmu 0.13 JSON-based interface, using dev-libs/yajl.
	libvirtd	Builds the libvirtd daemon as well as the client utilities instead of just the client utilities
	lvm	Allow using the Logical Volume Manager (sys-apps/lvm2) as pool for disk image storage
	lxc	Support management of Linux Containers virtualisation (app-emulation/lxc)
	macvtap	Support for MAC-based TAP (macvlan/macvtap). For networking instead of the normal TUN/TAP. It has its advantages and disadvantages. macvtap support requires very new kernels and is currently evolving. Support for this is experimental at best.
	nfs	Allow using Network File System mounts as pool for disk image storage
	numa	Use NUMA for memory segmenting via sys-process/numactl
	openvz	Support management of OpenVZ virtualisation (see sys-kernel/openvz-sources)
	parted	Allow using real disk partitions as pool for disk image storage, using sys-block/parted to create, resize and delete them.
	pcap	Support auto learning IP addreses for routing
	phyp	Support management of virtualisation through the PHYP hypervisor protocol.
	qemu	Support management of QEmu virtualisation (one of app-emulation/qemu, app-emulation/qemu-kvm or app-emulation/qemu-spice)
	uml	Support management of User Mode Linux virtualisation
	virt-network	Enable virtual networking (NAT) support for guests. Includes all the dependencies for NATed network mode. Effectively any network setup that relies on libvirt to setup and configure network interfaces on your host. This can include bridged and routed networks ONLY if you are allowing libvirt to create and manage the underlying devices for you. In some cases this requires enabling the 'netcf' USE flag (currently unavailable).
	virtualbox	Support management of VirtualBox virtualisation (one of app-emulation/virtualbox or app-emulation/virtualbox-ose)
	xen	Support management of Xen virtualisation (app-emulation/xen)
libvirt-glib	introspection	Use dev-libs/gobject-introspection for introspection
libvirt-glib	vala	Enable bindings for dev-lang/vala
libvirt-sandbox	introspection	Use dev-libs/gobject-introspection for introspection
lxc	vanilla	Avoid adding Gentoo Linux-specific modifications, which include the custom init script. This is present as a flag to avoid forcing dependencies over users that might not want have them around as they use LXC in contexts where the init script is not useful.
mol	oldworld	Includes Macintosh's OldWorld support
	pci	Experimental PCI proxy support
	sheep	Support for the sheep net driver
open-vm-tools	doc	Generate API documentation
	fuse	Build vmblock-fuse in favor of FUSE based blocking mechanism for DnD
	pic	Force shared libraries to be built as PIC
	unity	Enable host unity support
opennebula	qemu	Pull in packages needed to create Qemu/Kvm nodes.
opennebula	xen	Pull in packages needed to create Xen nodes.
q4wine	gnome	Use the gksu sudo GUI for managing the devices
	icoutils	Enable icoutils support
	kde	Use the kdesu sudo GUI for managing the devices
	wineappdb	Enable Win AppDB browser subsystem
qemu	aio	Enables support for Linux's Async IO
	brltty	Adds support for braille displays using brltty
	curl	Adds support for read-only block device emulation based on files located on http and ftp servers
	esd	Enable esound output for sound emulation
	fdt	Enables firmware device tree support
	gnutls	Enable TLS support for the VNC console server
	kqemu	Enables the kernel acceleration module on a x86/x86-64 cpu
	kvm	Use the KVM (Kernel Virtual Machine) infrastructure on compatible hardware
	ncurses	Enable the ncurses-based console
	nss	Enable opengl/x11 output for lm32 target.
	pulseaudio	Enable pulseaudio output for sound emulation
	qemu-ifup	Provides the qemu-ifup script for use with QEMU's built in bridging
	rbd	Enable rados block device backend support, see http://ceph.newdream.net/wiki/QEMU-RBD
	sdl	Enable the SDL-based console
	spice	Enable Spice protocol support via app-emulation/spice
	ssl	Enable TLS support for the VNC console server
	static	Enable static build, useful to chroot in user-mode emulation
	usbredir	Use sys-apps/usbredir to redirect USB devices to another machine over TCP
	vde	Enable Virtual Distributed Ethernet (VDE) based networking
	vhost-net	Enable accelerated networking using vhost-net, see http://www.linux-kvm.org/page/VhostNet
	xattr	Add support for getting and setting POSIX extended attributes, through sys-apps/attr. Requisite for the virtfs backend.
	xen	Enables support for Xen backends
	xfs	Support specific optimizations when files are stored on XFS filesystem.
qemu-kvm	aio	Enables support for Linux's Async IO
	alsa	Enable alsa output for sound emulation
	brltty	Adds support for braille displays using brltty
	esd	Enable esound output for sound emulation
	fdt	Enables firmware device tree support
	jpeg	Enable JPEG compression for the VNC console server
	ncurses	Enable the ncurses-based console
	nss	Build support for Smartcard devices emulation using dev-libs/nss
	png	Enable PNG compression for the VNC console server
	pulseaudio	Enable pulseaudio output for sound emulation
	qemu-ifup	Provides the qemu-ifup script for use with QEMU's built in bridging
	rbd	Enable rados block device backend support, see http://ceph.newdream.net/wiki/QEMU-RBD
	sdl	Enable the SDL-based console
	spice	Enable Spice protocol support via app-emulation/spice
	ssl	Enable TLS support for the VNC console server
	usbredir	Use sys-apps/usbredir to redirect USB devices to another machine over TCP
	vde	Enable VDE-based networking
	vhost-net	Enable accelerated networking using vhost-net, see http://www.linux-kvm.org/page/VhostNet
	xattr	Add support for getting and setting POSIX extended attributes, through sys-apps/attr. Requisite for the virtfs backend.
	xen	Enables support for Xen backends
spice	client	Build the spicec client app (does not reduce dependencies at the moment).
spice	gui	Build some GUI components (inside the guest window).
spice-vdagent	consolekit	Use sys-auth/consolekit to determine the master vdagentd in case of multiple running vdagentds (highly recommended)
uae	scsi	Enable the uaescsi.device
	sdl-sound	Use media-sound/sdl-sound for audio output
	ui	Build the user interface (could be gtk or ncurses based, depending on sdl, dga, svga and aalib USE flags)
vice	ethernet	Enable ethernet emulation
	memmap	Enable extra monitor features
	xrandr	Enable support for the X xrandr extension
virt-manager	policykit	Enables sys-auth/polkit authentication support, required when using app-emulation/libvirt with PolicyKit authentication
	sasl	Depend on the proper libraries needed to connect to SASL-enabled libvirtd instances (e.g. Kerberos-protected instances).
	spice	Support connecting to SPICE-enabled virtual machines.
virt-viewer	gtk3	Link against x11-libs/gtk+:3 instead of x11-libs/gtk+:2
	spice	Support connecting to SPICE-enabled virtual machines.
	vnc	Support connecting to VNC-enabled virtual machines.
virtualbox	additions	Install Guest System Tools ISO
	extensions	Install extension module packages
	headless	Build without any graphic frontend
	sdk	Enable building of SDK
	vboxwebsrv	Build and install the VirtualBox webservice
virtualbox-bin	additions	Install Guest System Tools ISO
	chm	Install kchmviewer binary to enable online help (in MS CHM format)
	headless	Install without any graphic frontend
	rdesktop-vrdp	Install the rdesktop client integration
	sdk	Enable building of SDK
	vboxwebsrv	Install the VirtualBox webservice
virtualbox-modules	pax_kernel	Apply patch needed for pax enabled kernels
vmware-player	vmware-tools	Install VMware Tools images
vmware-workstation	ovftool	Install OVF tool.
	server	Install VMware Workstation Server component.
	vix	Install VIX. The VIX API allows you to write programs and scripts that automate virtual machine operations, and run programs or manipulate files within guest operating systems.
	vmware-tools	Install VMware Tools images
vov	gprof	build with profiling support
wine	capi	Enable ISDN support via CAPI
	custom-cflags	Bypass strip-flags; use are your own peril
	gecko	Add support for the Gecko engine when using iexplore
	opencl	Enable OpenCL support
	perl	Install helpers written in perl (winedump/winemaker)
	samba	Add support for NTLM auth. see http://wiki.winehq.org/NtlmAuthSetupGuide and http://wiki.winehq.org/NtlmSigningAndSealing
	udisks	Support dynamic storage devices using sys-fs/udisks
	win32	Build a 32bit version of Wine (won't run Win64 binaries)
	win64	Build a 64bit version of Wine (won't run Win32 binaries)
xen	acm	Enable the ACM/sHype XSM module from IBM
	flask	Enable the Flask XSM module from NSA
	pae	Enable support for PAE kernels (usually x86-32 with >4GB memory)
	xsm	Enable the Xen Security Modules (XSM)
xen-tools	acm	Enable the ACM/sHype XSM module from IBM for xen-3
	api	Build the C libxenapi bindings
	flask	Enable the Flask XSM module from NSA
	hvm	Enable support for hardware based virtualization (VT-x,AMD-v)
	ioemu	Enable IOEMU support
	pygrub	Install the pygrub boot loader
	qemu	Enable IOEMU support via the use of qemu-dm
	screen	Enable support for running domain U console in an app-misc/screen session
	xend	Enable support the xend and xm to manage xen

app-forensics

Package	Flag	Description
afflib	fuse	Enable extra fuse thingies
	qemu	Enable qemu stuff
	s3	Enable support for Amazon S3
aide	audit	Enable support for sys-process/audit
aide	prelink	Enable support for sys-devel/prelink
chkrootkit	cron	Install cron script for weekly rootkit scans
libewf	ewf2	Enables the v2 API
libewf	rawio	Enables raw IO handling
openscap	nss	Prefer NSS over libgcrypt as the crypto engine
	rpm	Compiles the RPM probes
	sql	Build the sql independant probes
ovaldi	rpm	Enable the RPM probes
rdd	rawio	Enables raw IO handling
sleuthkit	aff	Enable extra aff formats
	dbtool	Add patch for dbtool interface from PyFlag
	ewf	Enable libewf support

app-i18n

Package	Flag	Description
anthy	canna-2ch	Enable support for app-dicts/canna-2ch
fcitx	gtk3	Use GTK+3 instead of 2
	opencc	Enable OpenCC for Chinese Transform
	pango	Enable support for x11-libs/pango
ibus	dconf	Enable support for gnome-base/dconf
	gconf	Enable support for gnome-base/gconf
	gtk3	Enable support for gtk+3
	introspection	Use dev-libs/gobject-introspection for introspection
	vala	Enable support for dev-lang/vala
ibus-m17n	gtk	Build the preference interfaces, based on x11-libs/gtk+ (GTK+ 2).
ibus-mozc	ibus	Enable support for app-i18n/ibus
ibus-mozc	scim	Enable support for app-i18n/scim
ibus-pinyin	boost	Compile against dev-libs/boost libraries
ibus-pinyin	opencc	Enable support for app-i18n/opencc
ibus-table-xingma	extra-phrases	Add extra phrases into builded Engine
ibus-unikey	gtk3	Enable support for gtk+3
im-ja	anthy	Support for Anthy input method
im-ja	skk	Support for SKK input method
imsettings	xfconf	Enable integration in the Xfce desktop environment with xfce-base/xfconf
kimera	anthy	Support for Anthy input method
libtomoe-gtk	gucharmap	Enable gucharmap dictionary plugin
scim-tomoe	gucharmap	Enable gucharmap dictionary plugin
tomoe	hyperestraier	Enable support for app-text/hyperestraier
uim	anthy	Enable support for app-i18n/anthy input method
	eb	Enable support for dev-libs/eb
	gtk3	Enable support for x11-libs/gtk+:3
	prime	Enable support for app-i18n/prime
	skk	Enable support for app-i18n/skk-jisyo

app-laptop

Package	Flag	Description
ibam	gkrellm	Enable building of app-admin/gkrellm module
laptop-mode-tools	scsi	Adds dependency on sdparm to control non-SATA SCSI drivers
pbbuttonsd	ibam	Enable support for Intelligent Battery Monitoring
pbbuttonsd	macbook	Enable support for the Macbook and Macbook Pro
prey	alarm	Module for playing an audio file
	alert	Display a warning message when the computer seems to be stolen"
	geo	Module for retrieving the physical location of the stolen computer
	lock	Lock stolen computer
	network	Get network information (active connections, traceroute) from stolen computer
	secure	Delete or hide sensitive user data
	session	Get screenshots from user session
	userpriv	Create a prey user group so regular users can access and modify the prey configuration. Use it with caution
	webcam	Use computer's webcam to take screenshots of the thief
tp_smapi	hdaps	Install a compatible HDAPS module
tpctl	tpctlir	Enable support for thinkpad models 760 and 765

app-misc

Package	Flag	Description
anki	furigana	Enable support for furigana generation
	graph	Enable support for making graphs
	recording	Enable support for audio recording
	sound	Enable support for adding sound to cards
beagle	chm	Enables support for indexing of the MS CHM (Compressed HTML) file format using app-doc/chmlib.
	debug	Enables debug XML dumps of all messages passed between the daemons and the UIs. WARNING, this option will fill up your Beagle Log directory very quickly.
	doc	Builds programmer documentation for Beagle using app-doc/monodoc.
	eds	Enables Beagle to index the Addressbook and Calendar from mail-client/evolution stored in gnome-extra/evolution-data-server. The information is accessed using dev-dotnet/evolution-sharp.
	firefox	Compiles and installs the extension for either www-client/firefox or www-client/firefox-bin. This extension helps Beagle index the websites you visit.
	galago	Allows Beagle to get status information from applications such as Pidgin to show in the search results.
	google	Enables google (gmail etc.) indexing support.
	gtk	Enables the GTK+ Beagle Search UI for showing search results. This is the default GUI for Beagle.
	inotify	Enable inotify filesystem monitoring support
	ole	Enables OLE (Object Linking and Editing) support via dev-dotnet/gsf-sharp, app-text/wv, and app-office/gnumeric(ssindex). These allow Beagle to index MS Powerpoint, Word, and Spreadsheet Documents.
	pdf	Enables support for indexing of the PDF (Portable Document Format) file format using `pdfinfo` and `pdftotext` from app-text/poppler
	thunderbird	Compiles and installs the extension for either mail-client/thunderbird or mail-client/thunderbird-bin. This extension helps Beagle index your mails.
	xscreensaver	Allow Beagle to detect when the screensaver is switched on. This allows Beagle to use more resources and index faster when the computer is not in use.
ddccontrol	ddcpci	enable direct PCI memory access (the setuid ddcpci util)
digitemp	ds2490	Build support for the ds2490 sensor
	ds9097	Build support for the ds9097 sensor
	ds9097u	Build support for the ds9097u sensor
freemind	groovy	Build plugin for scripting via Groovy
	latex	Build plugin for inserting mathematical formulas in LaTeX syntax
	pdf	Build plugin for exporting mindmaps to SVG and PDF
	svg	Build plugin for exporting mindmaps to SVG and PDF
gcstar	stats	Enable statistics reporting
gcstar	tellico	Enable support for kde-misc/tellico files
geneweb	ocamlopt	Enable ocamlopt support (dev-lang/ocaml native code compiler)
geoclue	geonames	Install geonames.org provider
	gpsd	Install sci-geosciences/gpsd provider
	gsmloc	Install GSM location provider
	gtk	Install gtk-based geoclue-test-gui
	hostip	Install hostip.info provder
	manual	Install manual provider
	nominatim	Install openstreetmap.org provider
	plazes	Install plazes.com provider
	skyhook	Install skyhookwireless.com provider
	yahoo-geo	Install Yahoo geolocation provider
gnote	applet	Enable gnote applet for gnome-base/gnome-panel
gourmet	gnome-print	Enable pretty Python printing with gnome-print
gourmet	rtf	Enable export to RTF
gpsdrive	gdal	Include gdal and ogr support for format conversions.
	kismet	Include support for kismet wifi mapping.
	mapnik	Include mapnik support for custom map creation.
	scripts	Include some of the additional helper scripts.
	speech	Include speech support.
gramps	reports	All external software that is needed for graphical reports will be installed
gramps	webkit	Use Webkit-based rendering for geographical data view.
graphlcd-base	g15	Add support for app-misc/g15daemon driver (e.g. Logitech G15 Keybord)
lcd-stuff	mpd	Add support for display of mpd controlled music (media-libs/libmpd)
lcd4linux	mpd	Add support for display of mpd controlled music (media-libs/libmpd)
lcdproc	ftdi	Enable support for FTDI connections in some selected LCD_DEVICES (currently hd44780)
	irman	Enable support for IRMan (media-libs/libirman)
	nfs	Adds support for NFS file system
	seamless-hbars	Try to avoid gaps in horizontal bars
lirc	hardware-carrier	The transmitter device generates its clock signal in hardware
lirc	transmitter	Add transmitter support to some lirc-drivers (e.g. serial)
mc	edit	Compile and install the mcedit application
	mclib	Compile and install the libmc.so shared library
	xdg	Toggles mc's config dir location. Enable for $XDG_CONFIG_HOME/mc, disable for $HOME/.mc
note	general	Add support for ascii flatfile backend
note	text	Add support for text backend
recoll	audio	Index audio files
	camelcase	Enable indexing for camelCase sentences and words
	chm	Index chm files
	dvi	Index dvi files
	ics	Index iCalendar files
	info	Index GNU info files
	inotify	Use the Linux Kenrel notification subsystem for monitoring file alterations in realtime
	lyx	Index Latex lyx files
	msdoc	Index Microsoft Word documents
	msppt	Index Microsoft PowerPoint documents
	msxls	Index Microsoft Excel documents
	pdf	Index PDF documents
	ps	Index PostScript files
	rtf	Index Microsoft RTF documents
	session	Stop monitoring file alterations when X11 session terminates
	tex	Index TeX files
	wordperfect	Index WordPerfect documents
	xml	Index several XML-based formats (Abiword, FictionBook, Kword, Office OpenXML, OpenDocument, SVG)
roadnav	festival	Enable support for app-accessibility/festival
	flite	Enable support for app-accessibility/flite (festival-lite)
	openstreetmap	Enable openstreetmap support
	scripting	Enable scripting support
screen	multiuser	Enable multiuser support (by setting correct permissions)
screen	nethack	Express error messages in nethack style
sphinx	id64	use 64-bit document and word IDs
sphinx	stemmer	Enable language stemming support
strigi	clucene	Enable dev-cpp/clucene backend support.
	hyperestraier	Enable app-text/hyperestraier backend support.
	inotify	Enable support for inotify.
	log	Enables advanced logging through dev-libs/log4cxx.
tablix	pvm	Add support for parallel virtual machine (sys-cluster/pvm)
tasque	hiveminder	Allows you to use http://www.hiveminder.com/ as your storage backend.
tasque	rememberthemilk	Allows you to use http://www.rememberthemilk.com/ as your storage backend.
tomboy	galago	Add support for the galago desktop presence framework (dev-dotnet/galago-sharp)
towitoko	moneyplex	Makes libtowitoko work for the moneyplex home banking software
tracker	applet	Build tracker monitor applet
	firefox-bookmarks	Install bookmark data miner plugin for www-client/firefox and www-client/firefox-bin
	flickr	Build flickr data miner
	gsf	Enable gnome-extra/libgsf based data extractor and for ODT.
	introspection	Use dev-libs/gobject-introspection for introspection
	iptc	Enable extraction of IPTC data from pictures
	laptop	Make tracker power management aware
	nautilus	Enable tracker to integrate with gnome-base/nautilus by providing entries in its context menu
	playlist	Add support for playlists
	strigi	Add support for app-misc/strigi search engine.
	thunderbird	Install email data miner plugin for mail-client/thunderbird and mail-client/thunderbird-bin
	upnp	Add support for video extraction via media-libs/gupnp-dlna.
vifm	compatibility	Compatibility with previous versions of vifm
	extended-keys	Support for extended keys (arrows, home etc)
	magic	Use libmagic to determine mimetypes
	vim-plugin	Install the vifm vim plugin
worker	avfs	Enable support for sys-fs/avfs
workrave	distribution	Enable networking. See http://www.workrave.org/features/

app-mobilephone

Package	Flag	Description
gammu	irda	Enables infrared support
gnokii	ical	Enable support for dev-libs/libical
	irda	Enable infrared support
	sms	Enable SMS support (build smsd)
obexd	nokia	Add support for Nokia backup plugin
obexd	server	Enables server installation, it's incompatible with obex-data-server provided one
smstools	stats	Enable statistic reporting
yaps	capi	Enable CAPI support

app-office

Package	Flag	Description
abiword	collab	Enable collaborative editing plugin
	grammar	Enable grammar checking via dev-libs/link-grammar
	math	Enable support for x11-libs/gtkmathview
	openxml	Enable OpenXML support
	ots	Enable Text Summarizer plugin
	plugins	Enable plugins build (see http://www.abisource.com/wiki/PluginMatrix for more information). If your file cannot be opened due lack of support, try enabling this.
	thesaurus	Enable thesaurus support
	wordperfect	Enable wordperfect file support via app-text/libwpd
calligra	attica	Get hot stuff with dev-libs/libattica
	eigen	Enable dev-cpp/eigen mathematical templates support
	glew	Enable media-libs/glew opengl extension library support
	glib	Enable support for C library routines from dev-libs/glib
	gsf	Enable support for ODT structures extraction via gnome-extra/libgsf
	kdcraw	Enable support for KDE image manipulating interface via kde-base/libkdcraw
	kdepim	Enable support for KDEPIM resources integration
	marble	Enable displaying of maps using Marble
	mso	Enable support for various MS Office TM file formats
	okular	Enable bindings for kde-base/okular
	openctl	Enable support for transformation algorithms via media-libs/opengtl
	word-perfect	Enable support for various WordPerfect file formats
	xbase	Enable support for xbase compatible database formats
	xslt	Enable xslt and exslt support format support
glabels	barcode	Enable barcode support through external libraries.
gnucash	chipcard	Enable support for chipcard reading and processing.
	hbci	Enable HBCI support, for connecting to some internet banks
	quotes	Enable Online Stock Quote retrieval
	webkit	Use net-libs/webkit-gtk for rendering rather than gnome-extra/gtkhtml
gnumeric	gnome	Allow Gnumeric to use GNOME specific extensions.
	perl	Enable perl plugin loader.
	python	Enable python plugin loader.
imposter	iksemel	Enable external dev-libs/iksemel parsing support
karbon	pstoedit	Build support for PDF and PS import.
karbon	wpg	Build wordperfect image support.
kexi	reports	Enable the reports koffice module in kchart, also used by kplato and kexi
kexi	xbase	Build support for xbase db types.
kmymoney	hbci	Enable HBCI support using net-libs/aqbanking
kmymoney	quotes	Enable Online Stock Quote retrieval
koffice-libs	reports	Enable the reports koffice module in kchart, also used by kplato and kexi
koffice-meta	reports	Enable the reports koffice module in kchart, also used by kplato and kexi
krita	gmm	Enable library for sparse, dense and skyline matrices.
krita	kdcraw	Enable KDE image manipulating interface.
kspread	solver	Use solver extension for solving lingebra and others.
kword	wpd	Build wordperfect document support.
libreoffice	binfilter	Enable support for legacy StarOffice 5.x and earlier file formats
	graphite	Enable support for non-Roman fonts via media-gfx/graphite2
	gtk3	Enable highly experimental gtk3 frontend
	jemalloc	Use dev-libs/jemalloc for allocations
	odk	Build the Office Development Kit
	pdfimport	Build pdf-import extension using app-text/poppler. Note that you don't need this for pdf-export!
	templates	Enable installation of Sun templates
	vba	Enable support for VBA compatibility and ActiveX embedding
	webdav	Adds support for HTTP repositories via net-libs/neon
	xmlsec	Adds support for document signing using internal modified dev-libs/xmlsec and system dev-libs/nss
libreoffice-bin	offlinehelp	Download and install help files locally instead of using the LibreOffice Wiki
libreoffice-l10n	offlinehelp	Install help files locally instead of using the LibreOffice Wiki
libreoffice-l10n	templates	Enable installation of Sun templates
lyx	aspell	Add support for aspell spellchecking
	dia	Add support for diagrams (app-office/dia)
	docbook	Add support for docbook export
	dot	Add support for DOT import (media-gfx/graphviz)
	enchant	Add support for enchant spellchecking wrapper (both aspell and hunspell can be used by LyX).
	gnumeric	Add support for importing Gnumeric/OpenOffice/MS Excel spreadsheets into LyX.
	html	Add support for HTML import
	hunspell	Add support for spellchecking based on hunspell and reuse system-wide OpenOffice dictionaries. This also enable thesaurus dictionaries not accessible via aspell.
	luatex	Add support for LuaTeX typesetting
	monolithic-build	This should speed up compilation significantly when you have enough RAM (> 600 MB)
	rcs	Add support for revision control via dev-vcs/rcs
	rtf	Add support for RTF import/export packages
	xetex	Add support for XeTeX typesetting
rabbit	gs	Ghostscript support (app-text/ghostscript-gpl)
rabbit	tgif	tgif support (media-gfx/tgif)
scribus	linguas_cs_CZ	Language support for cs_CZ
	linguas_da_DK	Language support for da_DK
	linguas_de_1901	Language support for de_1901
	linguas_de_CH	Language support for de_CH
	linguas_en_AU	Language support for en_AU
	linguas_lt_LT	Language support for lt_LT
	linguas_pl_PL	Language support for pl_PL
	linguas_sa	Language support for sa
	linguas_sk_SK	Language support for sk_SK
	linguas_th_TH	Language support for th_TH
	minimal	Don't install headers (only required for e.g. plug-in developers)
	templates	Document tamplates
texmacs	netpbm	Add support for media-libs/netpbm
texstudio	video	Use phonon for video embedding
tpp	figlet	Install app-misc/figlet to support the --huge command

app-pda

Package	Flag	Description
barry	boost	Enable boost support
	gui	Install the GUI backup tool
	opensync	Install the barry-sync plugin for OpenSync 0.22
gtkpod	webkit	Enable webkit support for browsing and downloading album covers
libopensync-plugin-irmc	irda	Enable infrared support
libopensync-plugin-syncml	http	Enable http transports
libopensync-plugin-syncml	obex	Enable obex transports
libsyncml	http	Enable http transports
libsyncml	obex	Enable obex transports
synce-sync-engine	opensync	Enable OpenSync (app-pda/libopensync) python plug-in

app-portage

Package	Flag	Description
conf-update	colordiff	Use colors when displaying diffs (app-misc/colordiff)
eix	bzip2	Support for parsing of environment.bz2 to guess repository name of packages installed with ancient portage versions (requires app-arch/bzip2). This flag is safe to disable for portage users that have re-merged all packages since 2007. This flag will be phased out.
	debug	Build with upstream's CXXFLAGS/LDFLAGS for debugging support; not recommended for normal use.
	doc	Create description of the eix cache file additionally in html format
	hardened	Add CXXFLAGS/LDFLAGS enhancing security at the cost of a slight speed loss. If a hardened gcc is used, these flags should not make a difference.
	nls	Support foreign language messages (experimental; currently only de)
	optimization	Accept upstream's choices for CXXFLAGS/LDFLAGS for optimization. Absense of this USE flag does not strip user's *FLAGS
	security	This adds some checks which can prevent certain exploits if e.g. the eix code has a bug. If you use the hardened toolchain, using this flag does not increase security and can even lead to problems.
	sqlite	Compile in support for portage's sqlite backend; to actually use it you need additional configuration of portage and eix
	strong-optimization	Adds several more agressive CXXFLAGS/LDFLAGS for optimization like graphite (if available). May cause trouble with some buggy compiler versions. Absense of this USE flag does not strip user's *FLAGS
	tools	Create separate binary for script helper tools (currently only: versionsort); useful if they are called extremely often
gentoolkit	minimal	Install only the gentoolkit core code.
layman	bazaar	Support dev-vcs/bzr based overlays
	darcs	Support dev-vcs/darcs based overlays
	git	Support dev-vcs/git based overlays
	mercurial	Support dev-vcs/mercurial based overlays
pfl	network-cron	Adds a cron job which does a weekly submit of the package database
portato	eix	Enable eix support
portato	userpriv	Allow emerge processes as normal user
tatt	templates	Install template scripts to be used with tatt

app-shells

Package	Flag	Description
bash	bashlogger	Log ALL commands typed into bash; should ONLY be used in restricted environments such as honeypots
	mem-scramble	Build with custom malloc/free overwriting allocated/freed memory
	net	Enable /dev/tcp/host/port redirection
	plugins	Add support for loading builtins at runtime via 'enable'
pdsh	rsh	This allows the use of rsh (remote shell) and rcp (remote copy) for authoring websites. sftp is a much more secure protocol and is preferred.
scsh-install-lib	scsh	Use a non-FHS directory layout
shish	diet	Use dev-libs/dietlibc
tcsh	catalogs	Add support for NLS catalogs

app-text

Package	Flag	Description
asciidoc	highlight	Enable source code highlighting
calibre	udisks	Add run-time dependency on sys-fs/udisks in order to mount and unmount reading devices.
cb2bib	poll	use clipboard polling
crm114	mew	Add support for using the mewdecode mime decoder (app-emacs/mew)
	mimencode	Add support for using the mimencode mime (net-mail/metamail)
	normalizemime	Add support for using the normalizemime (mail-filter/normalizemime)
cuneiform	imagemagick	Enables support of various input formats using media-gfx/imagemagick. Otherwise only uncompressed BMP files are supported.
dictd	judy	Build Judy-based (dev-libs/judy) plugin implementing fast "exact" and especially "lev" strategies
dictd	minimal	Don't build server but dict client, dictzip and dictfmt only.
docbook-sgml-utils	jadetex	Add support for app-text/jadetex (for processing tex files produced by the TeX backend of Jade)
dvipng	t1lib	Enable support for T1lib font rendering (media-libs/t1lib)
enchant	aspell	Adds support for app-text/aspell spell checker
	hunspell	Adds support for app-text/hunspell spell checker
	zemberek	Adds support for app-text/zemberek-server spell checker server
evince	dvi	Enable the built-in DVI viewer
	gnome	Enable the use of gnome-base/gconf to honour lockdown settings
	introspection	Use dev-libs/gobject-introspection for introspection
	nautilus	Enable property page extension in gnome-base/nautilus
	t1lib	Enable the Type-1 fonts for the built-in DVI viewer (media-libs/t1lib)
	xps	Enable XPS viewer using app-text/libgxps
ghostscript-gpl	bindist	Disable dejavu support for binary distribution because of licensing issue
gonzui	lha	Enable LHA archive support
	rpm	Enable rpm support
	zip	Enable ZIP archive support
gtranslator	http	Enable support for open translation plugin using net-libs/libsoup
hyperestraier	mecab	Enable app-text/mecab support for Estraier
lcdf-typetools	kpathsea	Enable integration with kpathsea search library (TeX related)
libgxps	introspection	Use dev-libs/gobject-introspection for introspection
libwpd	tools	Build miscellaneous tools
libwpg	tools	Build miscellaneous tools
lodgeit	vim	Install a vim plugin allowing to paste and download from within vim
mathtex	png	Generate png images by default instead of gif
pandoc	highlight	Add support for syntax highlighting with dev-haskell/highlighting-kate
pdf2djvu	graphicsmagick	Enable media-gfx/graphicsmagick support
pdftk	nodrm	Decrypt a document with the user_pw even if it has an owner_pw set
podofo	boost	Add support for boost
poppler	exceptions	Enable exceptions throwing.
	introspection	Enable GObject introspection.
	utils	Install command-line PDF converters and various utilities.
sgmltools-lite	jadetex	Add support for app-text/jadetex (for processing tex files produced by the TeX backend of Jade)
stardict	editor	Build and install the stardict-editor utility
	espeak	Enable text to speech synthesizer using espeak engine
	festival	Enable text to speech synthesizer using festival engine
	gucharmap	Enable gucharmap dictionary plugin
	pronounce	Install WyabdcRealPeopleTTS package (it is just many .wav files) to make StarDict pronounce English words
	qqwry	Enable QQWry plugin, which provides information (in Chinese language) about geographical positions, owner, etc. for IP addresses
	tools	Build and install the extra stardict tools
sword	lucene	Enable lucene support for faster searching (dev-cpp/clucene)
texlive	context	Add support for the ConTeXt format (dev-texlive/texlive-context)
	detex	Add support for dev-tex/detex, a filter program that removes the LaTeX (or TeX) control sequences
	dvi2tty	Add support for dev-tex/dvi2tty to preview dvi-files on text-only devices
	dvipdfm	Add support for app-text/dvipdfm to convert DVI files to PDF
	extra	Add support for extra TeXLive packages
	games	Add typesetting support for games (chess, etc.) (dev-texlive/texlive-games)
	graphics	Add support for several graphics packages (pgf, tikz,...)
	humanities	Add LaTeX support for the humanities (dev-texlive/texlive-humanities)
	jadetex	Add support for app-text/jadetex (for processing tex files produced by the TeX backend of Jade)
	latex3	Add support for LaTeX3 (dev-texlive/texlive-latex3)
	luatex	Add extra support for luatex
	music	Add support for music typesetting (dev-texlive/texlive-music)
	omega	Add omega packages (dev-texlive/texlive-omega)
	pdfannotextractor	Add dev-tex/pdfannotextractor support, for extracting annotations from PDF files.
	pstricks	Add pstricks packages (dev-texlive/texlive-pstricks)
	publishers	Add support for publishers (dev-texlive/texlive-publishers)
	science	Add typesetting support for natural and computer sciences (dev-texlive/texlive-science)
	tex4ht	Add support for dev-tex/tex4ht (for converting (La)TeX to (X)HTML, XML and OO.org)
	xetex	Add support for XeTeX macros (dev-texlive/texlive-xetex)
	xindy	Add support for app-text/xindy, a flexible indexing system
texlive-core	xetex	Add support for XeTeX: a TeX system with Unicode and modern font technologies.
u2ps	fonts	Install a more complete set of unicode fonts
wdiff	experimental	Build experimental utilities (mdiff, unify, wdiff2)
webgen	builder	Enable programmatic HTML/XML generation
	exif	Enable EXIF information in image galleries
	highlight	Enable syntax highlighting for certain plugins
	markdown	Markdown support
	thumbnail	Thumbnail creation support using rmagick
wklej	vim	Install the vim plugin allowing to paste through ':Wklej'.
wpd2odt	gsf	Add support for structured files using gnome-extra/libgsf
	visio	Add support for visio format using media-libs/libvisio
	wpg	Add support for wpg format using app-text/libwpg
	wps	Add support for wps format using app-text/libwps
wv	tools	Install optional utilities considered deprecated in favor of using AbiWord.
xpdf	nodrm	Disable the drm feature decoder
yagf	cuneiform	Enable support for the app-text/cuneiform OCR engine.
yagf	tesseract	Enable support for the tesseract OCR engine

app-vim

Package	Flag	Description
gentoo-syntax	ignore-glep31	Remove GLEP 31 (UTF-8 file encodings) settings
vim-latex	html	Install HTML documentation

dev-cpp

Package	Flag	Description
glog	gflags	Use gflags module for flag parsing
pficommon	fcgi	Build FCGI feature
pficommon	mprpc	Build MessagePack RPC feature
sptk	aspell	Enable support for app-text/aspell
sptk	excel	Enable Excel support
xsd	ace	Enable support for serializing to/from an ACE CDR stream

dev-db

Package	Flag	Description
drizzle	curl	Enable the HTTP authentication plugin (using net-misc/curl). This is needed for the tests to apply properly.
	doc	Build the API documentation for the package, using app-doc/doxygen. Warning, this might take over an hour on slower machines.
	gearman	Enable the gearman plugins for user-defined functions and logging (using sys-cluster/gearman).
	haildb	Use the dev-db/haildb libraries to replace the innodb plugin storage engine with haildb (an innodb fork).
	md5	Enable the MD5 plugin, using dev-libs/libgcrypt; this replaces the older openssl and gnutls USE flags.
	memcache	Enable the memcache plugin for user-defined functions and statistics in I_S tables (using dev-libs/libmemcached). Currently restricts tests because of an upstream testsuite bug.
	pam	Enable the PAM authentication plugin (using sys-libs/pam). The configuration file created will be /etc/pam.d/drizzle.
firebird	client	Install client library and header files only
	superserver	Install SuperServer
	xinetd	Install ClassicServer
haildb	debug	Enable extra debug codepaths and assertions. If disabled, both the debug code and assertions are removed from the resulting binaries. Optimisations are untouched.
haildb	zlib	Add support for compressed tables through sys-libs/zlib.
ingres	client	Disable dbms component
	das	Enable das support
	demodb	Install demo DB
	net	Enable net support
	nodbms	Disable dbms component
maatkit	udf	Build the MySQL UDFs shipped with maatkit, requires non-minimal MySQL
mariadb	big-tables	Make tables contain up to 1.844E+19 rows
	cluster	Add support for NDB clustering (deprecated)
	community	Enables the community features from upstream.
	embedded	Build embedded server (libmysqld)
	extraengine	Add support for alternative storage engines (Archive, CSV, Blackhole, Federated(X), Partition)
	latin1	Use LATIN1 encoding instead of UTF8
	libevent	Use libevent for connection handling
	max-idx-128	Raise the max index per table limit from 64 to 128
	minimal	Install client programs only, no server
	oqgraph	Add support for the Open Query GRAPH engine
	pbxt	Add experimental support for PBXT storage engine
	profiling	Add support for statement profiling (requires USE=community).
	sphinx	Add suport for the sphinx full-text search engine
	test	Install upstream testsuites for end use.
mongodb	mms-agent	Install the MongoDB Monitoring Service agent
mongodb	v8	Use V8 JavaScript engine (dev-lang/v8) instead of SpiderMonkey (dev-lang/spidermonkey)
mysql	big-tables	Make tables contain up to 1.844E+19 rows
	cluster	Add support for NDB clustering (deprecated)
	community	Enables the community features from upstream.
	embedded	Build embedded server (libmysqld)
	extraengine	Add support for alternative storage engines (Archive, CSV, Blackhole, Federated(X), Partition)
	latin1	Use LATIN1 encoding instead of UTF8
	max-idx-128	Raise the max index per table limit from 64 to 128
	minimal	Install client programs only, no server
	pbxt	Add experimental support for PBXT storage engine
	profiling	Add support for statement profiling (requires USE=community).
	raid	Deprecated option, removed in the 5.0 series
	systemtap	Build support for profiling and tracing using dev-util/systemtap
	test	Install upstream testsuites for end use.
	xtradb	Add experimental support for Percona's InnoDB replacement: XtraDB
mysql-connector-c++	gcov	Build coverage support
phpmyadmin	setup	Installs the phpMyAdmin setup utility. Users who don't use the utility should disable this USE flag for security reasons as the setup tool was the target of various exploits in the past.
postgis	geos	Add the sci-libs/geos library for exact topological tests
	gtk	Build shp2pgsql-gui a graphical interface to shp2pgsql
	proj	Add the sci-libs/proj library for reprojection features
postgresql-base	pg-intdatetime	Enable --enable-integer-datetimes configure option, which changes PG to use 64-bit integers for timestamp storage
postgresql-base	pg_legacytimestamp	Use double precision floating-point numbers instead of 64-bit integers for timestamp storage.
postgresql-server	pg_legacytimestamp	Use double precision floating-point numbers instead of 64-bit integers for timestamp storage.
postgresql-server	uuid	Enable server side UUID generation (via dev-libs/ossp-uuid)
recutils	curl	Enable support for remote descriptors using libcurl
recutils	mdb	Build the mdb2rec utility
redis	jemalloc	Use dev-libs/jemalloc for allocations.
spatialite	geos	Add the sci-libs/geos library for exact topological tests
spatialite	proj	Add the sci-libs/proj library for reprojection features
sqlite	extensions	Enable support for dynamic loading of extensions
	fts3	Full text search using the fts3 module
	secure-delete	Overwrite deleted information with zeros in addition to marking the space as available for reuse. This causes a performance penalty.
	soundex	Enable the soundex function to compute soundex encodings of strings
	threadsafe	Enable thread safe operation of sqlite
	unlock-notify	Adds API for notifications when a database is unlocked in shared-cache mode
unixODBC	minimal	Disable bundled drivers and extra libraries (most users don't need these)
unixODBC	odbcmanual	Administrator, Internal Structure, Programmer and User documentation

dev-embedded

Package	Flag	Description
msp430-binutils	multislot	Allow for multiple versions of binutils to be emerged at once for same CTARGET
msp430-binutils	multitarget	Adds support to binutils for cross compiling (does not work with gas)
msp430-gcc	fixed-point	Enable fixed-point arithmetic support for MIPS targets in gcc (Warning: significantly increases compile time!)
	go	Build the GCC Go language frontend.
	graphite	Add support for the framework for loop optimizations based on a polyhedral intermediate representation
	libssp	Build SSP support into a dedicated library rather than use the code in the C library (DO NOT ENABLE THIS IF YOU DON'T KNOW WHAT IT DOES)
	mudflap	Add support for mudflap, a pointer use checking library
	multislot	Allow for SLOTs to include minor version (3.3.4 instead of just 3.3)
	objc	Build support for the Objective C code language
	objc++	Build support for the Objective C++ language
	objc-gc	Build support for the Objective C code language Garbage Collector
msp430-gdb	multitarget	Support all known targets in one gdb binary
msp430-gdb	python	Enable support for the new internal scripting language, as well as extended pretty printers
openocd	blaster	Enable support for Altera USE-Blaster
	dummy	Build the dummy port driver
	ftd2xx	Enable support for USB FTDI chips via dev-embedded/libftd2xx
	ftdi	Enable support for USB FTDI chips via dev-embedded/libftdi
	minidriver	Build the dummy minidriver
	parport	Enable support for parport JTAG devices
	presto	Enable support for AXIS PRESTO devices
	segger	Enable support for the Segger J-Link JTAG
	versaloon	Enable building support for the Versallon-lInk JTAG
ponyprog	epiphany	Enable support for www-client/epiphany
qvfb	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
sdcc	boehm-gc	Enable Hans Boehm's garbage collector (dev-libs/boehm-gc)
urjtag	ftdi	Enable support for USB FTDI chips (dev-embedded/libftdi)

dev-games

Package	Flag	Description
cegui	devil	Enable image loading via DevIL
	irrlicht	Enable the Irrlicht renderer
	ogre	Enable the OGRE renderer
	tinyxml	Enable the Tiny XML parser module
	xerces-c	Enable the Xerces-C++ XML parser module
	zip	Enable the Minizip resource provider
crystalspace	3ds	Enables support for .3DS files in CrystalSpace
	bullet	include support for Bullet library
	cal3d	include support for skeleton animation
	cegui	include support for Crazy Eddie GUI
	cg	NVIDIA toolkit plugin
	ode	include support for Open Dynamics Engine
guichan	allegro	Build the Allegro frontend
ode	double-precision	more precise calculations at the expense of speed
ode	gyroscopic	enable gyroscopic term (may cause instability)
ogre	cegui	build the CEGUI samples
	cg	NVIDIA toolkit plugin
	devil	image loading support with DevIL
	double-precision	more precise calculations at the expense of speed
openscenegraph	fox	Build examples using x11-libs/fox library
	gdal	Enable support for sci-libs/gdal library
	itk	Build dev-tcltk/itk plugin
	openinventor	Build OpenInventor plugin
	osgapps	Build osg applications
	xrandr	Enable support for the X xrandr extension
physfs	grp	Enable Build Engine GRP archive support
	hog	Enable Descent I/II HOG archive support
	mvl	Enable Descent I/II MVL archive support
	qpak	Enable Quake I/II QPAK archive support
	wad	Enable Doom WAD archive support
	zip	Enable ZIP archive support

dev-haskell

Package	Flag	Description
cabal-install	noprefs	Ignore 'preferred-versions' file from hackage's tarball.
citeproc-hs	bibutils	Use Chris Putnam's app-text/bibutils
citeproc-hs	network	Use dev-haskell/network and dev-haskell/http to retrieve CSL file from URIs.
gtk	gio	Add glib's GIO bindings.
highlighting-kate	executable	Build the Highlight executable
json	generic	Add support for generic encoder (dev-haskell/syb)
	parsec	Add support for parsing with Parsec
	pretty	Add support for using pretty printing combinators
texmath	cgi	Build texmath-cgi executable.

dev-java

Package	Flag	Description
ant	antlr	Enable ANTLR Ant tasks
	bcel	Enable bcel (bytecode manipulation) Ant tasks
	commonslogging	Enable commons-logging Ant tasks
	commonsnet	Enable commons-net Ant tasks
	jai	Enable JAI (Java Imaging) Ant task
	javamail	Enable JavaMail Ant task
	jdepend	Enable Jdepend Ant tasks
	jmf	Enable JMF (Java Media Framework) Ant tasks
	jsch	Disable Jsch (ssh, scp and related) Ant tasks
	log4j	Enable Apache log4j Ant tasks
	oro	Enable Apache Oro Ant tasks
	regexp	Enable Apache Regexp Ant tasks
	resolver	Enable Apache Resolver Ant tasks
	testutil	Enable optional test util classes
antlr	gunit	gUnit is a "Unit Test" framework for ANTLR grammars
antlr	script	Install a script to run antlr
bcel	findbugs	Include performance patch for findbugs package.
commons-collections	test-framework	Install the test framework
commons-logging	avalon-framework	Add optional support for avalon-framework
	avalon-logkit	Add optional support for avalon-logkit
	log4j	Add optional support for log4j
	servletapi	Add optional support for servletapi
commons-modeler	commons-digester	Add support for the commons-digester based Mbeans Descriptor source
diablo-jdk	jce	Enable Java Cryptographic Extension Unlimited Strength Policy files
ecj-gcj	native	Build a native binary along with the jar. Provides faster execution time, but needs about 1G memory and some patience to compile.
eclipse-ecj	ant	Support using ecj in Ant builds via dev-java/ant-eclipse-ecj
emma	launcher	Install /usr/bin/emma. Collides with sci-biology/emboss.
fop	hyphenation	Precompile hyphenation patterns from the dev-java/offo-hyphenation package and install them as fop-hyph.jar
	jai	Enable jai support
	jimi	Enable jimi support
gjdoc	xmldoclet	Also build support for the xml doclet that generates output in xml instead of the traditional html javadoc.
gnu-classpath	alsa	Build with ALSA javax.sound.midi provider
	dssi	Build with DSSI javax.sound.midi provider
	gconf	Build with GConf preferences backend
	gjdoc	Build GJDoc, a documentation generator
	gmp	Build with GMP backend for java.math.BigInteger
	gstreamer	Build with GStreamer javax.sound.sampler provider
	gtk	Build with Gtk+ AWT peers
	qt4	Build with Qt4 AWT peers
	xml	Build with native XML backend
ibm-jdk-bin	javacomm	Enable Java Communications API support
icedtea	cacao	Build additionally the CACAO virtual machine.
	hs20	Use the new version of HotSpot (20).
	jamvm	Build additionally the JamVM virtual machine.
	jbootstrap	If possible, recompile the final IcedTea executables with itself.
	nio2	Enable backport of NIO2 to OpenJDK6.
	nsplugin	Enable browser plugin (NPPlugin), requires also the webstart flag to be enabled.
	nss	Enable NSS security provider support.
	systemtap	Enable SystemTap probes in HotSpot.
	webstart	Enable Web Start support (via NetX).
	xrender	Enable support for using XRender with the AWT libraries.
	zero	Enable the zero assembler port of HotSpot.
icedtea-web	javascript	Enable support for using proxy auto config (PAC) files.
icedtea-web	nsplugin	Enable the browser plugin (NPPlugin).
itext	rtf	Build and provide libraries for rich text format
itext	rups	Build and provide GUI for Reading/Updating PDF Syntax
jcs	admin	Enable JCS Admin servlets
jdbc-jaybird	jni	Build/Install JDBC Type 2 native components
jdbc-mysql	c3p0	Enable c3p0 support
jdbc-mysql	log4j	Enable log4 support
jdbc-oracle-bin	dms	Enable support for the Oracle Dynamic Monitoring Service
jdbc-oracle-bin	ons	Enable support for the Oracle Notification Services (ONS) deamon
jna	awt	Enables support for Java AWT
jna	nio-buffers	Enables support for NIO buffers
jython	servletapi	Add optional support for servlet-api
log4j	javamail	Build the SMTPAppender
	jms	Build the JMSAppender
	jmx	Build org.apace.log4j.jmx
miglayout	swt	Add support for the SWT toolkit.
netbeans-nb	keychain	Automatically starts keychain on netbeans start and loads specified keys so Netbeans can use them.
oracle-jdk-bin	derby	Enable Installation of Bundled Derby (Java DB)
oracle-jdk-bin	jce	Enable Java Cryptographic Extension Unlimited Strength Policy files
oracle-jre-bin	jce	Enable Java Cryptographic Extension Unlimited Strength Policy files
proguard	ant	Ant task for using ProGuard in build.xml scripts
proguard	j2me	Adds support for J2ME Wireless Toolkit
rxtx	lfd	Installs and uses LockFileServer daemon (lfd)
sun-jdk	derby	Enable Installation of Bundled Derby (Java DB)
	jce	Enable Java Cryptographic Extension Unlimited Strength Policy files
	kernel_Solaris	Enable workaround for unpacking on Solaris
sun-jre-bin	jce	Enable Java Cryptographic Extension Unlimited Strength Policy files
swt	webkit	Embedded browser support via net-libs/webkit-gtk:2, replacing former xulrunner-based browser.
swt	xulrunner	Embedded browser support via xulrunner-1.9 (1.8 for swt-3.3). Xulrunner 2.0 is not supported, will be replaced by webkit in 3.7.

dev-lang

Package	Flag	Description
bas	lr0	Use the LR0 parser instead of the recursive descending parser
erlang	halfword	Enable halfword emulator
	hipe	HIgh Performance Erlang extension
	kpoll	Enable kernel polling support
	sctp	Support for Stream Control Transmission Protocol
fpc	ide	Build and install the Free Pascal Compiler IDE
gdl	grib	Add support for the meteorological GRIB format with sci-libs/grib_api
	gshhs	Add support for projection adn continent maps with sci-geosciences/gshhs-data
	hdf	Add support for the Hierarchical Data Format v.4
	proj	Add support for sci-libs/proj (geographic projections)
	ps	Add support for Postscript with dev-libs/pslib
	udunits	Add support for manipulating units of physical quantities
gforth	force-reg	Enable a possibly unstable GCC flag for possibly large performance gains
ghc	binary	Install the binary version directly, rather than using it to build the source version.
	ghcbootstrap	Internal: Bootstrap GHC from an existing GHC installation.
	llvm	Enable llvm code geenrator for ghc (-fllvm)
icc	eclipse	Install the dev-util/eclipse-sdk plugins
	idb	Install the Intel Debugger
	ipp	Install the Intel Integrated Primitive
	mkl	Install the Intel Math Kernel Library
icon	iplsrc	install the icon programming library source
idb	eclipse	Install the dev-util/eclipse-sdk plugins
	icc	Use dev-lang/icc to install idb (default)
	ifc	Use dev-lang/ifc to install idb
ifc	idb	Install the Intel Debugger
ifc	mkl	Install the Intel Math Kernel Library
logtalk	fop	Support for generating pdf documentation using fop
	gnupl	Support GNU Prolog back-end compiler
	qupl	Support Qu-Prolog back-end compiler
	swipl	Support SWI-Prolog back-end compiler
	xsbpl	Support XSB back-end compiler
	xslt	Support for generating html documentation using xslt
	yappl	Support YAP back-end compiler
lua	deprecated	make deprecated data structures/routines available
mercury	erlang	Support Mercury Erlang grade
mlton	binary	install a binary version (need to do this once to bootstrap, until smlnj is supported)
mono	pax_kernel	Enable if the user plans to run the package under a pax enabled hardened kernel
mono	xen	Make mono generate code that is considerably faster on xen VMs but slightly slower on for normal systems.
path64	assembler	Build PathAS
	debugger	Build PathDB
	native	Use EKOPath/Path64 for bootstraping
	valgrind	Use dev-util/valgrind for memory debbuging
perl	ithreads	Enable Perl threads, has some compatibility problems
perl	perlsuid	Enable Perl SUID install. Has some risks associated.
php	cli	Enable CLI SAPI
	discard-path	Switch on common security setting for CGI SAPI
	embed	Enable embed SAPI
	enchant	Add supports Enchant spelling library.
	fdftk	Add supports for Adobe's FDF toolkit.
	fileinfo	Add fileinfo extension support
	filter	Add filter extension support
	force-cgi-redirect	Switch on common security setting for CGI SAPI
	fpm	Enable the FastCGI Process Manager SAPI
	hash	Enable the hash extension
	intl	Enables the intl extension for extended internalization support
	json	Enable JSON support
	ldap-sasl	Add SASL support for the PHP LDAP extension
	mysqlnd	Use native driver for mysql, mysqli, PDO_Mysql
	pcre	Adds support for Perl Compatible Regular Expressions (deprecated: always "on" in php 5.3)
	pdo	Enable the bundled PDO extensions
	phar	Enables the phar extension to provide phar archive support
	pic	Force shared modules to build as PIC on x86 (speed tradeoff with memory usage)
	reflection	Enable the reflection extension (Reflection API) (deprecated: always "on" in php 5.3)
	spl	Adds support for the Standard PHP Library (deprecated: always "on" in php 5.3)
	suhosin	Add Suhosin support (patch and extension from http://www.suhosin.org/)
	xmlreader	Enable XMLReader support
	xmlwriter	Enable XMLWriter support
	zip	Enable ZIP file support
polyml	portable	Build the portable interpreter version of Poly/ML instead of native.
python	threads	Enable threading support. (DON'T DISABLE THIS UNLESS YOU KNOW WHAT YOU'RE DOING)
	wide-unicode	Enable wide Unicode implementation which uses 4-byte Unicode characters. Switching of this USE flag changes ABI of Python and requires reinstallation of many Python modules. (DON'T DISABLE THIS UNLESS YOU KNOW WHAT YOU'RE DOING)
	wininst	Install Windows executables required to create an executable installer for MS Windows.
qu-prolog	pedro	Pedro subscription/notification communications system
ruby	libedit	Use the dev-libs/libedit library to provide the readline extension, used for instance by the irb tool. This flag will take precedence over the readline USE flag. If neither libedit nor readline USE flags are enabled, the readline extension will not be built (and irb will lose line editing functionality).
	rdoc	Install dev-ruby/rdoc after installing Ruby.
	readline	Use the sys-libs/readline library to provide the readline extension, used for instance by the irb tool. This flag is meaningful only if the libedit USE flag is disabled. If neither libedit nor readline USE flags are enabled, the readline extension will not be built (and irb will lose line editing functionality).
	rubytests	Install ruby tests that can only be run after ruby is installed
	yaml	Use the dev-libs/libyaml library to build the psych extension, available since Ruby 1.9.2_rc2, in alternative to the bundled syck-based parser.
ruby-enterprise	fastthreading	EXPERIMENTAL Enables fast threading routines. Removes support for callcc.
	libedit	Use the dev-libs/libedit library to provide the readline extension, used for instance by the irb tool. This flag will take precedence over the readline USE flag. If neither libedit nor readline USE flags are enabled, the readline extension will not be built (and irb will lose line editing functionality).
	readline	Use the sys-libs/readline library to provide the readline extension, used for instance by the irb tool. This flag is meaningful only if the libedit USE flag is disabled. If neither libedit nor readline USE flags are enabled, the readline extension will not be built (and irb will lose line editing functionality).
	rubytests	Install ruby tests that can only be run after ruby is installed
scala	binary	Install from (Gentoo-compiled) binary instead of building from sources. Set this when you run out of memory during build.
spidermonkey	threadsafe	Build a threadsafe version of spidermonkey
swig	ccache	build ccache-swig(a fast compiler cache)
v8cgi	apache	Support for apache
	fcgi	Support for FastCGI
	memcached	Support for the memcached daemon
	xerces	Use the xerces XML parser
vala	vapigen	Enable vala's library binding generator

dev-libs

Package	Flag	Description
STLport	boost	Enable the usage of dev-libs/boost
ace	ciao	Include Component Intergraced Ace ORB into the build of ace
ace	tao	Include the ACE ORB (CORBA stuff) (called tao) into the build of ace
antlr-c	debugger	Compiles debug info into the library
apr	older-kernels-compatibility	Enable binary compatibility with older kernels
	urandom	Use /dev/urandom instead of /dev/random
	uuid	Enable UUID support
apr-util	nss	Install apr_crypto_nss module
apr-util	openssl	Install apr_crypto_openssl module
atk	introspection	Use dev-libs/gobject-introspection for introspection
boost	eselect	Run "eselect boost update" even if version is already selected
boost	tools	Build and install the boost tools (bcp, quickbook, inspect, wave)
check	subunit	Enable support for the subunit unit test protocol
cyberjack	fox	Enable installation of x11-libs/fox based fxcyberjack program
cyberjack	pcsc-lite	Enable installation of sys-apps/pcsc-lite driver
cyrus-sasl	authdaemond	Add Courier-IMAP authdaemond unix socket support (net-mail/courier-imap, mail-mta/courier)
	ldapdb	Enable ldapdb plugin
	ntlm_unsupported_patch	Add NTLM net-fs/samba NOT supported patch
	openldap	Add ldap support for saslauthd
	sample	Enable sample client and server
	srp	Enable SRP authentication
	urandom	Use /dev/urandom instead of /dev/random
e_dbus	bluetooth	Enable interfacing with net-wireless/bluez DBus API.
	connman	Enable interfacing with net-misc/connman DBus API.
	ofono	Enable interfacing with net-misc/ofono DBus API.
	test-binaries	Enable building of test binaries for enabled features
ecore	ares	Enables support for asynchronous DNS using the net-dns/c-ares library
	evas	Provides easy to use canvas by gluing media-libs/evas and various input/output systems.
	glib	Enable dev-libs/glib eventloop support
	inotify	Enable support for inotify
	tslib	Build with tslib support for touchscreen devices.
	xprint	Enable X11 Xprint support
efreet	cache	Enable caching of icons
eina	default-mempool	By default use system's allocator (pass-through) instead of custom choice for Eina's own data structures.
	mempool-buddy	Compile "buddy" memory pool allocation.
	mempool-chained	Compile "chained-pool" memory pool allocation.
	mempool-fixed-bitmap	Compile "fixed-bitmap" memory pool allocation.
	mempool-pass-through	Compile "pass-through" (system's malloc) memory pool allocation.
elfutils	lzma	Support automatic decompression of LZMA-compressed files and kernel images.
fcgi	html	Install HTML documentation
ferrisloki	stlport	Include support for dev-libs/STLport
folks	socialweb	Load web service contacts using net-libs/libsocialweb
	tracker	Load contacts from app-misc/tracker index
	utils	Build the folks-inspect utility
	vala	Regenerate pre-generated C code from Vala source
gdl	introspection	Use dev-libs/gobject-introspection for introspection
gecode	gist	Enable Gist, the Gecode Interactive Search Tool
geoip	perl-geoipupdate	Install pure perl version of geoipupdate, with Proxy Server support via via the "http_proxy" environment variable and easy to customize.
glib	introspection	Use dev-libs/gobject-introspection for introspection
	systemtap	Build support for profiling and tracing using dev-util/systemtap
	utils	Install gtester-report utility to generate test report files for your software.
igraph	arpack	Use external sci-libs/arpack
	blas	Use external virtual/blas numerical library
	gmp	Enables dev-libs/gmp support
	gprof	Enables profiling support
	lapack	Use external lapack numerical library
jemalloc	stats	Enable statistics calculation/reporting
json-glib	introspection	Use dev-libs/gobject-introspection for introspection
libappindicator	introspection	Use dev-libs/gobject-introspection for introspection
libburn	track-src-odirect	Read track input with O_DIRECT (see man 2 open), this may deliver a better write performance in some situations
libcdio	minimal	Only build the libcdio library and little more, just to be used to link against from multimedia players. With this USE flag enabled, none of the command-line utilities are built, nor is the CDDA library.
libcgroup	daemon	Install the configuration tools and init/config files.
libcgroup	tools	Install the cgroup rules processing daemon and init/config files.
libdbusmenu	introspection	Use dev-libs/gobject-introspection for introspection
libgdata	introspection	Use dev-libs/gobject-introspection for introspection
libgee	introspection	Use dev-libs/gobject-introspection for introspection
libgpg-error	common-lisp	Install common-lisp files
libgweather	introspection	Use dev-libs/gobject-introspection for introspection
libindicate	introspection	Use dev-libs/gobject-introspection for introspection
libisoburn	external-filters	Allow the use of external processes as file content filters (Note: this is a potential security risk)
libisoburn	external-filters-setuid	Also allow the use of external setuid processes as file content filters (Note: this is a potential security risk)
libisofs	verbose-debug	Enable verbose debug messages
libjit	interpreter	Enable the libjit interpreter
libjit	long-double	Enable the use of long double for jit_nfloat
libmail	apop	Enables the APOP authentication method
libmemcached	gtest	Build with libgtest support.
	hsieh	Use Hsieh hash algorithm.
	libevent	Use the libevent event loop interface.
libmix	no-net2	Disable support for net-libs/libpcap and net-libs/libnet
libnl	utils	Install command line interface utils
libowfat	diet	Compile against dev-libs/dietlibc
libp11	doc	Generate and install API documentation for the package.
libpcre	bzip2	Add support for pcregrep command to search within bzip2-compressed files, through sys-libs/zlib.
	jit	Enable Just-In-Time compilation of regexp bytecode to machine code, through the SLJIT compiler. This feature might conflict wtih security mitigation strategies such as NX/PaX as enabled by Gentoo Hardened.
	readline	Add support for command line editing to pcretest, through sys-libs/readline.
	recursion-limit	Limit match recursion to 8192; if disabled, the default limit is used, which is the same as the match limit.
	zlib	Add support for pcregrep command to search within gzip-compressed files, through app-arch/gzip.
libpeas	gjs	Build support for loading JavaScript plugins using dev-libs/gjs
	glade	Install the glade catalog
	python	Build support for loading dev-lang/python plugins
	seed	Build support for loading JavaScript plugins using dev-libs/seed
	vala	Build support for loading dev-lang/vala plugins
libprelude	easy-bindings	Enable support for high level bindings (available for C++, Perl, Python)
libprelude	swig	Enable rebuild of swig bindings
libpreludedb	swig	Enable rebuild of swig bindings
librra	recurrence	Enable recurrence support (EXPERIMENTAL)
libsqlora8	orathreads	Use Oracle threads
libtomcrypt	libtommath	Use the portable math library (dev-libs/libtommath)
libtomcrypt	tomsfastmath	Use the optimized math library (dev-libs/tomsfastmath)
libunique	introspection	Use dev-libs/gobject-introspection for introspection
link-grammar	aspell	Adds support for app-text/aspell spell checker
link-grammar	hunspell	Adds support for app-text/hunspell spell checker
log4cxx	smtp	Offer SMTP support via net-libs/libesmtp
m17n-lib	X	Builds the Graphical User Interface API and utilities for the package.
m17n-lib	gd	Build API and utilities based on media-libs/gd. This flag is only meaningful if the X USE flag is also enabled.
nss	utils	Install utilities included with the library
opencryptoki	tpm	Enable support for Trusted Platform Module (TPM) using app-crypt/trousers
openct	debug	Add debug output to the driver library for pcsc-lite.
openct	pcsc-lite	Build a driver library for sys-apps/pcsc-lite, providing PC/SC API access to devices supported by OpenCT.
openobex	irda	Enable IrDA support
opensc	libtool	Use sys-devel/libtool for dynamically loading libraries rather than the host libdl/dlopen helpers.
	openct	Use dev-libs/openct (and CT-API) for accessing Smartcard hardware. If neither openct nor pcsc-lite are enabled, only CT-API dynamic linking is enabled.
	pcsc-lite	Use sys-apps/pcsc-lite (and PC/SC API) for accessing Smartcard hardware. If neither openct nor pcsc-lite are enabled, only CT-API dynamic linking is enabled.
openssl	bindist	Disable EC/RC5 algorithms (as they seem to be patented)
openssl	rfc3779	Enable support for RFC 3779 (X.509 Extensions for IP Addresses and AS Identifiers)
pkcs11-helper	nss	Enable NSS crypto engine
ppl	lpsol	Build the ppl_lpsol linear programming problem solver
ppl	watchdog	Build the PPL Watchdog library - a C++ library for multiple, concurrent watchdog timers
seed	dbus	Build the JS module for sys-apps/dbus and dev-libs/dbus-glib
	mpfr	Build the JS module for dev-libs/mpfr
	profile	Build support for profiling dev-libs/seed for development purposes
	xml	Build JS module for dev-libs/libxml2
soprano	clucene	Enable dev-cpp/clucene backend support.
	raptor	Enables support for media-libs/raptor RDF parser/serializer.
	redland	Enables support for the dev-libs/redland storage backend (really slow one).
	virtuoso	Enables support for dev-db/virtuoso storage backend.
tinyxml	stl	Compile with TIXML_USE_STL support
tntnet	sdk	Enable tntnet SDK
tntnet	server	Enable tntnet server daemon
totem-pl-parser	archive	Enables support for accessing media files in archives transparently via app-arch/libarchive
	introspection	Use dev-libs/gobject-introspection for introspection
	quvi	Use media-libs/quvi for parsing video links
udis86	pic	Force shared libraries to be built as PIC
xapian	brass	Enabled brass backend db support
	chert	Enabled chert backend db support
	flint	Enabled flint backend db support
	inmemory	Enabled inmemory backend db support
	remote	Enabled remot backend db support
xerces-c	iconv	Use iconv (virtual/libiconv) as message loader and transcoder (in general it would be possible to use iconv only as message loader and something else like icu or the native method as transcoder and vice-versa, but this is a less common case and hard to handle)
	libwww	Use the net-libs/libwww library for fetching URLs, instead of the builtin method
	threads	Enable threading support through pthread (or other libraries on AIX, IRIX, HPUX, Solars). Highly recommended
xml-security-c	nss	Use dev-libs/nss for certain crypto operations (configureable at runtime)
xml-security-c	xalan	Enable support for XSLT and XPath parsing by dev-libs/xalan-c
xmlrpc-c	abyss	Build the Abyss mini web-server.
	libxml2	Use dev-libs/libxml2 to parse XML instead of the internal expat library.
	threads	Controls whether to build the Abyss web-server with pthreads or fork 'threading'.
	tools	Build the xmlrpc* tools.
xmlsec	gcrypt	Install xmlsec-gcrypt library
	gnutls	Install xmlsec-gnutls library
	nss	Install xmlsec-nss library
	openssl	Install xmlsec-openssl library
xqilla	faxpp	Use dev-libs/faxpp instead of Xerces-C for certain tasks
xqilla	htmltidy	Use app-text/htmltidy when parsing HTML
yaz	ziffy	Install ziffy, a promiscuous Z39.50 APDU sniffer

dev-lisp

Package	Flag	Description
abcl	clisp	Build Armed Bear Common Lisp using GNU CLISP
	cmucl	Build Armed Bear Common Lisp using CMU Common Lisp
	jad	Enable support for disassembling compiled code using JAD
clisp	hyperspec	Use local hyperspec instead of online version
	new-clx	Build CLISP with support for the NEW-CLX module which is a C binding to the Xorg libraries
	pari	Build CLISP with support for the PARI Computer Algebra System
	svm	Build CLISP with support for the Support Vector Machine module
cmucl	nosource	Don't include source code for CMUCL in installation
cmucl	source	Include source code for CMUCL in installation
ecls	gengc	Use generational garbage collection (experimental)
ecls	precisegc	Use type information during garbage collection (experimental)
gcl	ansi	Build a GCL with ANSI support (else build a traditional CLtL1 image)
	custreloc	Build a GCL which uses custom GCL code for linking
	dlopen	Build a GCL which uses dlopen for linking
	gprof	Build a GCL with profiling support
sbcl	cobalt	mips only: use mipsel binary instead of mips big endian binary to bootstrap
sbcl	ldb	Include support for the SBCL low level debugger

dev-lua

Package	Flag	Description
luarocks	curl	Uses net-misc/curl for fetching lua packages instead of net-misc/wget.
luarocks	openssl	Uses dev-libs/openssl for verifying lua packages instead of md5sum.

dev-ml

Package	Flag	Description
camlimages	gs	Ghostscript support (app-text/ghostscript-gpl)
lablgtk	glade	Enable libglade bindings compilation.
	gnomecanvas	Enable libgnomecanvas bindings compilation.
	sourceview	Enable GtkSourceView support
lwt	react	Enables support for dev-ml/react: Functional reactive programming (signals, events, etc.).
ocamlnet	cryptokit	Enables encryption support via dev-ml/cryptokit
	httpd	Enables net-httpd web server component
	zip	Enables netzip support to read/write gzip data using object channels

dev-perl

Package	Flag	Description
App-Nopaste	clipboard	copying of URLs with -x/--copy
	github	Github authentication
	pastebin	pastebin.com support
DBD-mysql	embedded	Support embedded server (libmysqld)
DBIx-Class	admin	Modules required for the DBIx::Class administrative library
	admin_script	Modules required for the CLI DBIx::Class interface dbicadmin
	deploy	Modules required for "deploy" in DBIx::Class::Storage::DBI and "deploymen_statements" in DBIx::Class::Storage::DBI
	replicated	Modules required for DBIx::Class::Storage::DBI::Replicated
Eidetic	auth	Enables dev-perl/Apache-AuthTicket based cookie authentication
GD	animgif	Enable animated gif support
Graphics-ColorNames	recommended	Install recommended support modules
HTML-Mason	modperl	Enable www-apache/mod_perl support
PDL	badval	Enable badval support
Panotools-Script	gui	Installs GUIs for some tools
Sysadm-Install	hammer	Enable hammer() funtion to run a command in the shell and simulate a user hammering the ENTER key to accept defaults on prompts

dev-php

Package	Flag	Description
PEAR-HTTP_Download	minimal	Do not include support for PEAR-MIME_Type
PEAR-HTTP_Download	postgres	Send postgres LOBs without buffering
PEAR-HTTP_Request2	curl	Force dev-lang/php to be compiled with curl extension
	fileinfo	Force dev-lang/php to be compiled with fileinfo extension
	ssl	Force dev-lang/php to be compiled with ssl extension
	zlib	Force dev-lang/php to be compiled with zlib extension
PEAR-PHP_Shell	auto-completion	Enable tab-completion
ZendFramework	cli	Enables the CLI
	doc	Installs the documentation
	examples	Installs the examples
	minimal	Installs the minimal version without Dojo toolkit, tests and demos
eaccelerator	contentcache	Enable content caching
	disassembler	Enable the eA disassembler
	doccommentinclusion	If you want eAccelerator to retain doc-comments in internal php structures.
	inode	Use inode-based caching
pecl-apc	lock_pthreadmutex	Enable pthread mutex locking
	lock_pthreadrw	Enable pthread read/write locking
	lock_semaphore	Enable semaphore locks instead of fcntl
	lock_spinlock	Enable spin locks (EXPERIMENTAL)
pecl-memcached	igbinary	Enable support for the igbinary serializer
smarty-docs	html	Install the documentation in HTML format
smarty-docs	pdf	Install the documentation in PDF format

dev-python

Package	Flag	Description
PyFoam	extras	Enable optional dependencies
PyQt4	X	Build the QtGui and QtDesigner modules
	assistant	Build the QtHelp and QtAssistant modules
	declarative	Build the QtDeclarative module
	kde	Select media-sound/phonon as Phonon variant needed for KDE
	multimedia	Build the QtMultimedia module
	opengl	Build the QtOpenGL module
	phonon	Build the phonon module
	sql	Build the QtSql module
	svg	Build the QtSvg module
	webkit	Build the QtWebKit module
	xmlpatterns	Build the QtXmlPatterns module
amqplib	extras	Install extra tools to generate initial Python mod from an AMQP XML file
anyvc	bazaar	Add support for Bazaar
	git	Add support for Git
	mercurial	Add support for Mercurial
atpy	fits	Enable support for reading and FITS with dev-python/pyfits.
atpy	votable	Enable support for reading and VOTABLE with dev-python/vo.
bpython	urwid	Backend based on dev-python/urwid
cgkit	3ds	Enable support for importing 3D Studio models
cvxopt	dsdp	Use interior point library sci-libs/dsdp
cvxopt	glpk	Use GNU Linear Programming Kit sci-mathematics/glpk
cython	numpy	Enable support for dev-python/numpy
dap	server	Enable OpenDAP server support
django-extensions	graphviz	Create a diagram of your database entity relationships using dev-python/pygraphviz.
	s3	Upload your media files to S3.
	vcard	Export your users email addresses to the vcard format.
docutils	glep	Install support for GLEPs
icalendar	doc	Generate examples and other extra documentation
ipython	matplotlib	Add support for dev-python/matplotlib
	mongodb	Enable support for MongoDB via dev-python/pymongo
	notebook	Install requirements for the web notebook based on www-servers/tornado
jinja	i18n	Enables support for i18n with dev-python/Babel
kaa-base	tls	SSL/TLS support via dev-python/tlslite
ldaptor	web	enable the web front end for ldaptor (uses dev-python/nevow)
markdown	pygments	Enable fancy pygments support
matplotlib	excel	Pull dev-python/xlwt for the exceltools toolkit
matplotlib	traits	Pull dev-python/traits for the experimental enthought traits support
mpmath	matplotlib	Add support for dev-python/matplotlib
numexpr	mkl	Enable support for Intel Vector Math Library, part of sci-libs/mkl.
paste	flup	enable support for flup (and therefore for various wgsi servers and middleware)
paste	openid	enable OpenID support
psycopg	mxdatetime	Enable support for MX DateTime and use it instead of Python's built-in datetime module
pygobject	introspection	Use dev-libs/gobject-introspection for introspection
pylons	genshi	Add optional genshi support
pylons	jinja	Add optional jinja support
pymongo	mod_wsgi	Disable the C extension to work with mod_wsgi.
pypax	xtpax	Enable XT_PAX and prefer it to PT_PAX.
pypy	jit	Enable the JIT compiler
pypy	sandbox	Enable sandboxing functionality
pyside	X	Build the QtGui and QtDesigner modules
	assistant	Build the QtHelp module
	declarative	Build the QtDeclarative module
	help	Build the QtHelp module
	kde	Select media-sound/phonon as Phonon variant needed for KDE
	multimedia	Build the QtMultimedia module
	opengl	Build the QtOpenGL module
	phonon	Build the phonon module
	script	Build the QtScript module
	sql	Build the QtSql module
	svg	Build the QtSvg module
	test	Build the QtTest module
	webkit	Build the QtWebKit module
	xmlpatterns	Build the QtXmlPatterns module
pytables	contrib	Install user-contributed files
pyudev	pygobject	Install PyGobject binding
	pyqt4	Install PyQt4 binding
	pyside	Install PySide binding
pyyaml	libyaml	enable libyaml support
pyzor	pyzord	enable support for pyzord
rdflib	redland	enable support for Redland triplestore
restkit	cli	Install the restcli command line interface/tool, based on dev-python/ipython
scrapy	boto	Add support for Amazon S3 via dev-python/boto
scrapy	ibl	Use Instace Based Learning alrogirithm for automatic extraction
spyder	ipython	Add support for dev-python/ipython
	matplotlib	Add support for dev-python/matplotlib
	numpy	Add support for dev-python/numpy
	pep8	Add support for dev-python/pep8
	pyflakes	Add support for dev-python/pyflakes
	pylint	Add support for dev-python/pylint
	rope	Add support for dev-python/rope
	scipy	Add support for sci-libs/scipy
	sphinx	Add support for dev-python/sphinx
sympy	imaging	Add support for dev-python/imaging
	ipython	Add support for dev-python/ipython
	mathml	Add support for mathml
	texmacs	Add support for app-office/texmacs
translate-toolkit	html	Support conversion between po and html files
	ical	Support conversion between po and ical files
	ini	Support conversion between po and ini files
	psyco	Use dev-python/psyco to speed up the execution time
	subtitles	Support conversion between po and sub files
twisted	serial	include serial port support
wxpython	doc	Install HTML wxWidgets docs and wxpython API reference.
wxpython	examples	Install interactive demo module browser and sample applets.
zsi	twisted	add support for dev-python/twisted

dev-ruby

Package	Flag	Description
barby	cairo	Add support for writing images (PNG, PS, EPS and, if supported, PDF and SVG) using dev-ruby/rcairo. Not available on JRuby.
	datamatrix	Add support for datamatrix 2D codes using dev-ruby/semacode.
	pdf-writer	Add support for writing PDF documents using dev-ruby/pdf-writer.
	png	Add support for writing PNG images using dev-ruby/chunky_png.
	prawn	Add support for writing PDF documents using dev-ruby/prawn.
	qrcode	Add support for QRCode 2D codes using dev-ruby/rqrcode.
	rmagick	Add support for writing images (among others PNG, GIF and JPEG) using dev-ruby/rmagick. Not available on JRuby.
camping	mongrel	Also install www-servers/mongrel
nokogiri	ffi	Use the Foreign Function Interface library (as provided by dev-java/jruby or dev-ruby/ffi depending on the implementation) rather than building a C extension to wrap around the libxml/libxslt interfaces. Note: JRuby always uses the FFI interface as native extensions are not supported.
rails	asset-pipeline	Also install the default components for the asset pipeline. These are not required but they are activated automatically in new Rails projects by default.
ruby-sdl	image	Enable media-libs/sdl-image support
	mixer	Enable media-libs/sdl-mixer support
	sge	Enable sdl-sge support
rubygems	server	Install support for the rubygems server

dev-scheme

Package	Flag	Description
bigloo	bglpkg	Build bglpkg binary, which can be use to access scmpkg servers (requires web)
	calendar	Build the embedded library for calendar programming
	crypto	Build the embedded cryptographic library
	debug	Enable extra debug codepaths
	doc	Install Bigloo Manual (HTML docs of Bigloo and r5rs)
	emacs	Build and install the Bigloo Developement Environment for Emacs (aka bee-mode)
	gmp	Adds support for dev-libs/gmp (GNU MP library)
	java	Enable the JVM backend for the Bigloo compiler
	mail	Mail library for email management (e.g. maildir and imap support)
	multimedia	Build multimedia library (e.g. for managing images). Needed for dev-scheme/hop
	openpgp	Build OpenPGP support (requires crypto)
	packrat	Bigloo port of Tony Garnock-Jones' packrat parser (requires srfi1)
	sqlite	Use the system-wide dev-db/sqlite
	srfi1	Build the srfi1 library: List library
	srfi27	Build the srfi27 library: Source of Random Bits (32bit-arch only, requires gmp)
	ssl	Adds support for SSL connections through dev-libs/openssl
	text	Library for dealing with text (e.g. BibTeX parser)
	threads	Enable thread support, it depends on dev-libs/boehm-gc built with threads use flag
	web	Library for web programming (e.g. XML, CGI parsers). Needed for dev-scheme/hop
chicken	parallel-build	Enable testing parallel build mode added in 4.7.3 version. Can still be not working
gauche-gl	cg	Enable NVidia Cg binding
gauche-gtk	glgd	Enable GL graph draw
guile	debug-freelist	Include garbage collector freelist debugging code
	debug-malloc	Include malloc debugging code
	deprecated	Enable deprecated features
	discouraged	(implied by deprecated) enable merely discouraged features
	elisp	Enable Emacs Lisp support
	networking	Include networking interfaces
	regex	Include regular expression interfaces
hop	debug	Enables building with debug symbols
	ssl	Enable SSL support for hop
	threads	Enable thread support for hop, it depends on dev-scheme/bigloo built with threads use flag.
kawa	awt	Assume AWT is available
	echo2	Enable support for the Echo2 web toolkit with dev-java/echo2
	frontend	Build "kawa" front-end program using sys-libs/readline
	jemacs	Build JEmacs
	krl	Build BRL emulation and KRL
	sax	Assume SAX2 is available with dev-java/sax
	servlets	Build support for generating servlets with dev-java/servletapi
	swing	Assume Swing is available
	swt	Assume SWT is available with dev-java/swt
	xqtests	Support XQuery Test Suite
racket	backtrace	Support GC backtrace dumps
	futures	Enable racket/future library for fine-grained hardware parallelism
	jit	Enable just-in-time compiler
	places	Enable racket/place library for share-nothing parallelism and message-passing communication. Compared to futures, places are heavyweight, but they have a simpler performance model.
	plot	Enable plot libraries
	threads	Enable support for green threads
scm	arrays	Support for arrays, uniform-arrays and uniform-vectors.
	bignums	Support for large precision integers.
	cautious	SCM will always check the number of arguments to interpreted closures.
	dynamic-linking	Be able to load compiled files while running.
	engineering-notation	Floats to display in engineering notation (exponents always multiples of 3) instead of scientific notation.
	gsubr	generalized c arguments: for arbitrary (more then 11) arguments to C functions.
	inexact	Support for floating point numbers.
	ioext	Commonly available I/O extensions: line I/O, file positioning, file delete and rename, and directory functions.
	macro	C level support for hygienic and referentially transparent macros (syntax-rules macros).
	regex	String regular expression matching.
	unix	Support for: nice, acct, lstat, readlink, symlink, mknod and sync.

dev-tcltk

Package	Flag	Description
expect-lite	debug	pull in packages needed for runtime interactive debugger
tktreectrl	shellicon	shellicon extension

dev-tex

Package	Flag	Description
abntex	lyx	Install with app-office/lyx layout
dot2texi	pgf	Enable support for dev-tex/pgf (The TeX Portable Graphic Format)
dot2texi	pstricks	Enable pstricks support
latex-beamer	lyx	Install with app-office/lyx layouts

dev-util

Package	Flag	Description
anjuta	devhelp	Enable devhelp integration
	glade	Build glade plugin for anjuta
	introspection	Use dev-libs/gobject-introspection for introspection
	packagekit	Use packagekit to search for missing tools
	sourceview	Build sourceview editing plugin for anjuta
	vala	Enable support for the Vala programming language
astyle	libs	builds and installs both shared and static library interfaces
buildbot	irc	Add support for status delivery through an ircbot.
	mail	Add support for watching a maildir for commits.
	manhole	Add support for manhole (debug over ssh)
catalyst	ccache	Enables ccache support
coccigrep	vim	Install the coccigrep vim plugin
codeblocks	contrib	Build additional contrib components
cppcheck	htmlreport	install cppcheck-htmlreport
ctags	ada	Enable Ada support
dialog	minimal	Disable library, install command-line program only
geany	vte	Enable Terminal support (x11-libs/vte)
geany-plugins	debugger	Enable the debugger plugin which interfaces with sys-devel/gdb
	devhelp	Enable the devhelp plugin which integrates dev-util/devhelp
	enchant	Enable spell checking using enchant
	gpg	Enable geanypg plugin which integrates GPG using app-crypt/gpgme
	gtkspell	Use gtkspell for dictionary support
	soup	Enable updatechecker plugin which requires net-libs/libsoup
	webkit	Enable webhelper plugin which requires net-libs/webkit-gtk
glade	introspection	Use dev-libs/gobject-introspection for introspection
global	vim	Integrate the GNU GLOBAL source code tag system with Vim
google-perftools	debug	Build a set of libraries with debug support (so-called debugalloc). These are available by default but are not needed unless you're actually developing using tcmalloc.
	largepages	Use (experimental) larger pages for tcmalloc, this increases memory usage, but should speed up the allocation/free operations.
	minimal	Only build the tcmalloc_minimal library, ignoring the heap checker and the profilers.
gtk-doc	highlight	Enable source code highlighting
gtk-doc	vim	Enable source code highlighting through app-editors/vim
kdevelop	cmake	Enable support for CMake build system
	okteta	Enable hex editor plugin
	qmake	Enable support for QMake build system
	qthelp	Enable support for QtHelp documentation browsing
kdevplatform	git	Enable Git version control support
kdevplatform	reviewboard	Enable reviewboard support
metro	ccache	Enable support for ccache
	git	Enable support for git snapshots
	threads	Enable support for pbzip2 tarball packing/unpacking
mono-tools	webkit	Use net-libs/webkit-gtk for rendering.
monodevelop	git	Enable Git version control support
nemiver	memoryview	Enable the optional hexadecimal memory inspection with app-editors/ghex.
nsis	config-log	Enable the logging facility (useful in debugging installers)
nvidia-cuda-sdk	cuda	Build CUDA binaries.
	emulation	Build binaries for device emulation mode. These binaries will not require a CUDA-capable GPU to run.
	opencl	Build OpenCL binaries.
nvidia-cuda-toolkit	debugger	Installs the CUDA debugger.
	opencl	Installs OpenCL utilities.
	profiler	Installs the NVIDIA CUDA visual profiler.
perf	demangle	Enable C++ symbol name demangling, using libbfd from sys-devel/binutils. When this flag is enabled, the package will have to be rebuilt after every version bump of binutils.
	doc	Build documentation and man pages. With this USE flag disabled, the --help parameter for perf and its sub-tools will not be available. This is optional because it depends on a few documentation handling tools that are not always welcome on user systems.
	perl	Add support for Perl as a scripting language for perf tools.
qdevelop	plugins	Build and install additional plugins
qt-creator	bazaar	Add support for dev-vcs/bzr version control system
	bineditor	Enable bineditor plugin
	bookmarks	Enable bookmarks plugin
	botan-bundled	Use the bundled copy of dev-libs/botan
	cmake	Enable cmake project manager plugin
	designer	Enable Qt Designer integration
	fakevim	Enable support for vim-like key bindings
	git	Add support for dev-vcs/git version control system
	madde	Enable integration with MADDE (Maemo Application Development and Debugging Environment)
	mercurial	Add support for dev-vcs/mercurial version control system
	perforce	Enable perforce software configuration manager plugin
	qml	Build QML support and many other QML-related tools (recommended)
	qtscript	Enable QtScript editor plugin
	valgrind	Add support for memory debugging using dev-util/valgrind
radare	gui	Enable the graphical user interface of radare (broken)
schroot	btrfs	Enable support for chroots using btrfs snapshots.
	dchroot	Enables the building of a wrapper named "dchroot", replacing sys-apps/dchroot.
	lvm	Enable support for chroots using LVM snapshots.
strace	aio	Enable dev-libs/libaio support for tracing Asynchronous I/O operations
universalindentgui	html	Add support for HTML files

dev-vcs

Package	Flag	Description
bzr	sftp	Enable sftp support
bzr-gtk	gconf	Enable GConf support
	gpg	Support signing with GnuPG.
	nautilus	Integrate with Nautilus file manager
	sourceview	Enable GtkSourceView support
cvs	server	Enable server support
cvs2svn	bazaar	Support for dev-vcs/bzr
cvs2svn	git	Support for dev-vcs/git
fossil	sqlite	Use the system SQLite instead of the bundled one
fromcvs	git	Add support for conversion to dev-vcs/git repositories
fromcvs	mercurial	Add support for conversion to dev-vcs/mercurial repositories
git	blksha1	Use the new optimized SHA1 implementation.
	cgi	Install gitweb too
	gtk	Include the gitview contrib tool.
	mozsha1	Makes git use an optimized SHA1 routine from Mozilla that should be fast on non-x86 machines.
	ppcsha1	Make use of a bundled routine that is optimized for the PPC arch.
	subversion	Include git-svn for dev-vcs/subversion support.
	webdav	Adds support for push'ing to HTTP repositories via DAV.
gitg	glade	Install a glade catalog file
gitolite	contrib	Install user-contributed files
gitolite-gentoo	contrib	Install user-contributed files
mercurial	bugzilla	Support bugzilla integration.
	gpg	Support signing with GnuPG.
	tk	Install dev-lang/tk for hgk script.
qct	bazaar	Support for dev-vcs/bzr
	mercurial	Support for dev-vcs/mercurial
	monotone	Support for dev-vcs/monotone
rabbitvcs	cli	Eanble console based frontend
	diff	Use for diff command dev-util/meld
	gedit	Enable plugin for app-editors/gedit
	git	Enable plugin for dev-vcs/git
	nautilus	Enable extension for gnome-base/nautilus
	thunar	Enable extension for xfce-base/thunar
subversion	ctypes-python	Build and install Ctypes Python bindings
	dso	Enable runtime module search
	extras	Install extra scripts (examples, tools, hooks)
	webdav-neon	Enable WebDAV support using net-libs/neon
	webdav-serf	Enable WebDAV support using net-libs/serf
svk	log4p	Enable perl logger support
	pager	Enable perl pager selection support
	patch	Enable patch creation, import support
tortoisehg	nautilus	Integrate with gnome-base/nautilus file manager

games-action

Package	Flag	Description
abuse	demo	Use the demo data instead of the full game
	levels	Install user-created levels (fRaBs)
	sound	Install optional sound data
chromium-bsu	mixer	Enables media-libs/sdl-mixer sound backend instead of media-libs/openal one.
d1x-rebirth	awe32	Enable AWE32 support
	demo	Use the demo data instead of the full game
	mixer	Enable mixer support
	mpu401	Enable MPU401 music support
d2x-rebirth	awe32	Enable AWE32 support
d2x-rebirth	mpu401	Enable MPU401 music support
openlierox	breakpad	Compile with support for breakpad crash reporting system

games-arcade

Package	Flag	Description
bomns	editor	enables building the level editor
burgerspace	network	Enable client-server support
jumpnbump	music	Enable playing of background music
lbreakout2	themes	Install additional themes
moleinvasion	music	Download and install the music files
slimevolley	net	Enable network support
smc	music	Download and install the music files
triplexinvaders	psyco	psyco python accelerator
tuxanci	physfs	Use dev-games/physfs instead of dev-libs/libzip to load compressed data
tuxanci	sound	Enable sound
ultrastar-ng	songs	Install a few demo songs
ultrastar-ng	video	Enable smpeg video support

games-board

Package	Flag	Description
chessdb	tb4	Install 4 pieces table bases
crafty	no-opts	Don't try to enable crazy CFLAG options
freedoko	backgrounds	Install additional background images
	gnomecards	Install the gnome-games card set
	kdecards	Install the KDE card set
	net	Enable network game support
	openclipartcards	Install the openclipartcards card set
	pysolcards	Install the PySol card set
	xskatcards	Install the XSkat card set
grhino	gtp	Install the GTP (Go/Game Text Protocol) frontend
pasang-emas	extras	Install some extra themes
pysolfc	extra-cardsets	Install extra cardsets
pysolfc	sound	Enable sound support usingdev-python/pygame
spider	athena	Enable athena widgets
xboard	default-font	Install the default font that xboard uses
xboard	zippy	Enable experimental zippy client

games-emulation

Package	Flag	Description
generator	sdlaudio	Enable SDL Audio
snes9x	netplay	Enable playing ROMs over the network (not recommended)
snes9x	xrandr	Enable support for the X xrandr extension
vbam	link	Enable GBA linking functionality
xmess	net	Add network support

games-engines

Package	Flag	Description
frobtads	tads2compiler	Build TADS2 compiler
frobtads	tads3compiler	Build TADS3 compiler
scummvm	fluidsynth	compile with support for fluidsynth

games-fps

Package	Flag	Description
alienarena	vidmode	Link against x11-libs/libXxf86vm. Required for full-screen support.
darkplaces	cdsound	Enables using CD audio in the engine
	demo	Uses the demo data from quake1 (quake1-demodata)
	lights	Install and setup the updated light maps
	textures	Install and setup the updated textures
doom-data	doomsday	Add wrapper to run it within doomsday
doom3	roe	Adds support for the Resurrection of Evil expansion
duke3d	demo	Install the demo files
duke3d	pic	disable optimized assembly code that is not PIC friendly
ezquake-bin	security	install the security module needed for some servers
lsdldoom	freedoom	Install games-fps/freedoom wad file
	net	Enables network game support
	shareware	Install games-fps/doom-data for shareware wad file
nexuiz	maps	Install the community map pack
quake2-icculus	demo	Install the demo files (quake2-demodata) and configure for use
	qmax	Build the pretty version (quake max)
	rogue	Build support for the 'Ground Zero' Mission Pack (rogue)
	xatrix	Build support for the 'The Reckoning' Mission Pack (xatrix)
quake3	mumble	Adds player-location (positional audio) support to VoIP
	teamarena	Adds support for Team Arena expansion pack
	voice	Adds VoIP support
quake3-bin	teamarena	Adds support for Team Arena expansion pack
qudos	demo	Install the demo files (quake2-demodata) and configure for use
	mods	Build support for the quake2 mission packs
	qmax	Build the pretty version (quake max)
	textures	Install the enhanced textures (quake2-textures)
rott	demo	Install the shareware version
unreal-tournament-goty	S3TC	Add the extra fancy textures to UT ... only works on certain cards (nvidia/ati/s3)
warsow	angelscript	Enable AngelScript support
warsow	irc	Enable IRC support
worldofpadman	maps	Install extra maps (PadPack)

games-kids

Package	Flag	Description
gcompris	gnet	will let GCompris fetch content from a web server

games-misc

Package	Flag	Description
xcowsay	fortune	Installs the fortune-mod xcow binary

games-mud

Package	Flag	Description
tf	atcp	enable ATCP support.
	gmcp	enable GMCP support.
	option102	enable telnet option 102 support.

games-puzzle

Package	Flag	Description
cuyo	music	Enable playing of background music
jag	editor	Install level editor
jag	extras	Install additional graphics
xlogical	alt_gfx	Use alternate graphics which are closer to the original Amiga version

games-roguelike

Package	Flag	Description
angband	sound	Enable and install sounds

games-rpg

Package	Flag	Description
daimonin-client	music	Install extra music
drascula	sound	Install optional audio files
eternal-lands-data	bloodsuckermaps	Will install Bloodsucker's Maps in place of the official map files.
	music	Adds in-game music.
	sound	Adds in-game sound effects.
kqlives	cheats	Enable cheating mode
nwn	hou	Install the Hordes of the Underdark expansion pack
nwn	sou	Installs the Shadows of Undrentide expension pack
nwn-data	hou	Install the Hordes of the Underdark expansion pack
	nowin	For those people who cant grab the 1.2 gigs of data files from a windows partition
	sou	Installs the Shadows of Undrentide expension pack

games-simulation

Package	Flag	Description
openttd	aplaymidi	Enables midi music in game, using aplaymidi as an external player
	dedicated	Build only the openttd server, and not the client.
	lzo	Enables LZO compression for savegames. This is only needed to load extremely old savegames. (versions before 0.2)
	openmedia	Enables the free open media sets: OpenGFX, OpenSFX, OpenMSX, removing the requirement for proprietary TTD assets to play OpenTTD.
singularity	music	Install music files

games-sports

Package	Flag	Description
xmoto	editor	Depend on inkscape, scripts to convert svg to level (svg2lvl)

games-strategy

Package	Flag	Description
dark-oberon	fmod	Add sound support (fmod)
defcon-demo	system-libs	Use system libraries instead of the ones included in the upstream distribution.
freeciv	auth	Add authentication capability
	ggz	Add support for GGZ Gaming Zone
	sound	Add support for sound provided by media-libs/sdl-mixer
glest	editor	Also install a level editor
heroes3	maps	Installs optional map data
	music	Installs optional music data
	sounds	Installs optional sound data
naev	mixer	Enables media-libs/sdl-mixer sound backend in addition to media-libs/openal one.
ufo-ai	editor	Build map editor
uqm	music	download and install music files (large)
	remix	download and install music remix files (large)
	voice	download and install voice files (large)
wesnoth	server	Enable compilation of server
wesnoth	tinygui	enable GUI reductions for resolutions down to 320x240 (PDAs)
x2	bonusscripts	Add bonus scripts
	dynamic	Use dynamic binaries instead of static
	langpacks	Install additional language packs
	modkit	Install the modkit

games-util

Package	Flag	Description
gslist	web	Enable the web interface
pyfa	graph	Enable support for graphs

gnome-base

Package	Flag	Description
dconf	introspection	Use dev-libs/gobject-introspection for introspection
dconf	vala	Add support for dev-lang/vala
gconf	introspection	Use dev-libs/gobject-introspection for introspection
	ldap	Build backend which enables default mail accounts, addressbooks and calendars for Evolution to be configured using each user's LDAP entry."
	orbit	Use gnome-base/orbit for IPC, same as in gconf-2.x
gdm	consolekit	Allow proper handling of removable media according to who is actually present on the machine.
	dmx	Enables Distributed Multihead X (DMX) support
	fallback	Install x11-wm/metacity as fallback in case gnome-shell greeter fails to start
	fprint	Enables experimental fingerprint authentication using sys-auth/fprintd
	gnome-shell	Enables a greeter based on GNOME Shell (uses OpenGL)
	introspection	Use dev-libs/gobject-introspection for introspection
	remote	Enables support for secure remote connections
	smartcard	Enables experimental smartcard authentication
	xklavier	Use x11-libs/libxklavier for keyboard management
gnome	extras	Install additional GNOME applications
gnome	fallback	Install gnome-base/gnome-panel and x11-wm/metacity for the GNOME 3 fallback mode
gnome-control-center	cheese	Add support for taking pictures for the user accounts panel using media-video/cheese
	colord	Support color management using x11-misc/colord
	socialweb	Add support for configuring social web service settings using net-libs/libsocialweb
gnome-desktop	introspection	Use dev-libs/gobject-introspection for introspection
gnome-extra-apps	shotwell	Install the media-gfx/shotwell photo manager
gnome-extra-apps	tracker	Install the app-misc/tracker indexer and the GNOME packages that require it
gnome-light	automount	Use gnome-base/gvfs[gdu] for automounting of drives in nautilus
	fallback	Install gnome-base/gnome-panel and x11-wm/metacity for the GNOME 3 fallback mode
	gnome-shell	Install gnome-base/gnome-shell and x11-wm/mutter for the standard GNOME 3 desktop mode
gnome-menus	introspection	Use dev-libs/gobject-introspection for introspection
gnome-panel	bonobo	Enable Bonobo compatibility modules for applets still not ported to DBUS.
gnome-panel	introspection	Use dev-libs/gobject-introspection for introspection
gnome-settings-daemon	colord	Support color management using x11-misc/colord
	packagekit	Enable support for the distro-neutral package manager GUI app-admin/packagekit
	short-touchpad-timeout	Change the touchpad timeout so that it's effective for fast typists
gvfs	afp	Enables support for accessing AFP (Apple Filing Protocol) network shares
	archive	Enables support for accessing files in archives transparently via app-arch/libarchive
	bluray	Enable playback of Blu-ray filesystems using media-libs/libbluray
	fuse	Enables fuse mount points in $HOME/.gvfs for legacy application access
	gdu	Enable sys-apps/gnome-disk-utility integration
	gnome	Enable support for reading settings from gnome-base/gconf and for the special network:/// URL
	http	Enable the HTTP/DAV backend using net-libs/libsoup-gnome
	udev	Enable udev base replacement code for cdda feature
libgnomecanvas	glade	Enable glade support
libgnomekbd	introspection	Use dev-libs/gobject-introspection for introspection
libgtop	introspection	Use dev-libs/gobject-introspection for introspection
librsvg	gtk3	Build with gtk+-3 support
	introspection	Use dev-libs/gobject-introspection for introspection
	tools	Build miscellaneous tools
nautilus	introspection	Use dev-libs/gobject-introspection for introspection
	packagekit	Use packagekit to search for programs to open unknown file types
	previewer	Use gnome-extra/sushi to preview files from the file mananger
	sendto	Enable the nautilus-sendto extension to send files to various locations/devices
	tracker	Add support for app-misc/tracker search

gnome-extra

Package	Flag	Description
avant-window-navigator	gconf	Enable GConf as configuration backend
avant-window-navigator	vala	Enable installation of dev-lang/vala binding
avant-window-navigator-extras	gconf	Enable GConf as configuration backend
avant-window-navigator-extras	webkit	Enable support for net-libs/webkit-gtk
evolution-data-server	gnome-online-accounts	Enable using net-libs/gnome-online-accounts for authorization
	introspection	Use dev-libs/gobject-introspection for introspection
	vala	Build dev-lang/vala bindings
	weather	Enable optional weather calendar support
file-browser-applet	gtkhotkey	Enable hotkey support via x11-libs/gtkhotkey
gdesklets-core	dbus	Enable gDesklets Controls to use DBus
gnome-color-manager	clutter	Use media-libs/clutter to render color gamut representations
gnome-color-manager	packagekit	Enable support for the distro-neutral package manager GUI app-admin/packagekit
gnome-do-plugins	banshee	Enables the Banshee (media-sound/banshee) plugin
gnome-dvb-daemon	totem	Build a plugin for media-video/totem
gnome-dvb-daemon	vala	Add support for dev-lang/vala
gnome-games	aisleriot	Install the card game Aisleriot (Solitaire)
	artworkextra	Installs extra artwork for various games
	clutter	Install games that use media-libs/clutter
	glchess	Install Chess written in dev-lang/vala and OpenGL
	introspection	Use dev-libs/gobject-introspection for introspection
	seed	Install swell-foop and lightsoff which are written in JavaScript using dev-libs/seed
	sudoku	Install the game Sudoku which uses dev-python/pygobject and introspection
gnome-media	twolame	Allow encoding MPEG Audio Layer 2 (MP2) files using twolame
gnome-power-manager	applet	Build battery monitor applet
gnome-utils	bonobo	Enable applets (gdict one) still not ported to DBUS, requiring deprecated bonobo support in gnome-panel.
gucharmap	introspection	Use dev-libs/gobject-introspection for introspection
libgda	canvas	Enable support for x11-libs/goocanvas
	http	Enable embedded net-libs/libsoup based server
	introspection	Use dev-libs/gobject-introspection for introspection
	json	Enable support for JSON format
	mdb	Enable support for Microsoft Access database using app-office/mdbtools
	sourceview	Enable support for x11-libs/gtksourceview
	vala	Enable bindings for dev-lang/vala
libgsf	gtk	Enable use of gdk in thumbnailer
libgsf	thumbnail	Enable libgsf supported formats thumbnailer
mousetweaks	applet	Build the gnome-base/gnome-panel applet
music-applet	mpd	Enable MPD support
nautilus-sendto	gajim	Enables support for net-im/gajim
	mail	Enables support for mailto using gnome-extra/evolution-data-server
	pidgin	Enables support for net-im/pidgin
	upnp	Enables support for sending files over upnp using net-libs/gupnp-av
panflute	mpd	Enable MPD support
polkit-gnome	introspection	Use dev-libs/gobject-introspection for introspection
synapse	ayatana	Build in support for Ayatana notification using the libindicate plugin
	plugins	Build support for plugins using librest
	zeitgeist	Add support for Zeitgeist event tracking system
zeitgeist	fts	Enable the full text search extension
zeitgeist-datasources	bzr	Zeitgeist plugin for dev-vcs/bzr as data source
	chromium	Zeitgeist plugin for www-client/chromium as data source
	emacs	Zeitgeist plugin for emacs as data source
	eog	Zeitgeist plugin for media-gfx/eog as data source
	firefox	Zeitgeist plugin for www-client/firefox as data source
	geany	Zeitgeist plugin for dev-util/geany as data source
	gedit	Zeitgeist plugin for app-editors/gedit as data source
	rhythmbox	Zeitgeist plugin for media-sound/rhythmbox as data source
	telepathy	Zeitgeist plugin for telepathy framework as data source
	tomboy	Zeitgeist plugin for app-misc/tomboy as data source
	totem	Zeitgeist plugin for media-video/totem as data source
	vim	Zeitgeist plugin for vim as data source
	xchat	Zeitgeist plugin for net-irc/xchat-gnome as data source
zenity	compat	Installs gdialog for compatibility with older shell scripts which uses dev-lang/perl
zenity	webkit	Enable HTML rendering using net-libs/webkit-gtk

gnustep-apps

Package	Flag	Description
cdplayer	preferences	Use gnustep-apps/preferences for preferences setting
cdplayer	systempreferences	Use gnustep-apps/systempreferences for preferences setting
gnumail	emoticon	Enable extra Emoticon Bundle to see smiley's in e-mail messages

gnustep-base

Package	Flag	Description
gnustep-back-art	xim	Enable X11 XiM input method
gnustep-back-cairo	xim	Enable X11 XiM input method
gnustep-back-xlib	xim	Enable X11 XiM input method
gnustep-make	libobjc2	Enables use of the GNUstep Objective-C runtime (gnustep-base/libobjc2) with sys-devel/clang compiler
gnustep-make	native-exceptions	Enables use of the native Objective-C exception support (@try/@catch/@finally) built-in objective-c exceptions with compilers that support it

gpe-base

Package	Flag	Description
gpe	games	Builds and installs GPE games.

kde-base

Package	Flag	Description
ark	archive	Enable support for a variety of archive formats through libarchive
cantor	R	Enable R backend support
	analitza	Enable support kde-base/analitza
	ps	Enable rendering EPS files
dolphin	thumbnail	Enables video thumbnails generation for kde-base/dolphin file manager.
dolphin-plugins	bazaar	Enable support for the bazaar VCS
	git	Enable support for the git VCS
	mercurial	Enable support for the mercurial VCS
gwenview	kipi	Support for the KDE Image Plugin Interface.
kaccessible	speechd	Enable support for the speech-dispatcher speech synthesizer
kalzium	editor	Enable the embedded molecule editor/viewer
kalzium	solver	Enable the equation solver
kde-meta	sdk	Pull in developer-specific meta-packages
kdeartwork-kscreensaver	eigen	Enable various arithmetic screensavers which use Eigen2 for computations.
kdeartwork-kscreensaver	kexiv2	Enable image rotation based on exif tags with libkexiv2.
kdebase-data	wallpapers	Install the KDE wallpapers
kdebase-kioslaves	sftp	Enable SFTP protocol support using net-libs/libssh
kdebase-meta	wallpapers	Install the KDE wallpapers
kdebase-startkde	wallpapers	Install the KDE wallpapers
kdebindings-csharp	akonadi	Compile bindings for Akonadi.
	phonon	Compile bindings for Phonon.
	plasma	Compile bindings for KDE's Plasma.
	qimageblitz	Compile bindings for media-libs/qimageblitz.
	qscintilla	Compile bindings for x11-libs/qscintilla.
	webkit	Compile bindings for x11-libs/qt-webkit.
kdebindings-meta	csharp	Enable C# language bindings for KDE and Qt
kdebindings-perl	akonadi	Compile bindings for Akonadi.
	attica	Compile bindings for dev-libs/libattica.
	declarative	Compile bindings for x11-libs/qt-declarative.
	kate	Compile bindings for KDE Advanced Text Editor.
	multimedia	Compile bindings for x11-libs/qt-multimedia.
	okular	Compile bindings for kde-base/okular.
	phonon	Compile bindings for Phonon.
	plasma	Compile bindings for KDE's Plasma.
	qimageblitz	Compile bindings for media-libs/qimageblitz.
	qscintilla	Compile bindings for x11-libs/qscintilla.
	qthelp	Compile bindings for QtHelp from x11-libs/qt-assistant.
	qwt	Compile bindings for x11-libs/qwt.
	webkit	Compile bindings for x11-libs/qt-webkit.
kdebindings-ruby	akonadi	Compile bindings for Akonadi.
	declarative	Compile bindings for x11-libs/qt-declarative.
	kate	Compile bindings for KDE Advanced Text Editor.
	okular	Compile bindings for kde-base/okular.
	phonon	Compile bindings for Phonon.
	plasma	Compile bindings for KDE's Plasma.
	qscintilla	Compile bindings for x11-libs/qscintilla.
	qwt	Compile bindings for x11-libs/qwt.
	webkit	Compile bindings for x11-libs/qt-webkit.
kdelibs	opengl	Enable OpenGL support for Plasma (GLApplet)
	udisks	Use udisks for block device access (e.g., automounting)
	upnp	Enable UPnP support
	upower	Use upower for power management
kdenetwork-meta	ppp	Enable support for net-dialup/ppp.
kdepimlibs	prison	Enable support for QRcodes in contacts
kdeplasma-addons	attica	Enable support for dev-libs/libattica
	desktopglobe	Enable Desktop Globe wallpaper using kde-base/marble
	qalculate	Enable Qalculate runner using sci-libs/libqalculate
	qwt	Enable applets that use x11-libs/qwt:5.
	scim	Enable applets that use app-i18n/scim.
kdesdk-misc	extras	Build po2xml and swappo tools
kdeutils-meta	floppy	Install kde-base/kfloppy to format and create DOS or ext2fs filesystems in a floppy.
kdm	consolekit	Enables support for authorization using consolekit
kget	bittorrent	Enable bittorrent transfer plugin through net-libs/libktorrent
kget	webkit	Enable KdeWebkit browser plugin using kde-misc/kwebkitpart
kig	kig-scripting	Support Python scripting
kimono	akonadi	Compile bindings for Akonadi.
kimono	plasma	Compile bindings for KDE's Plasma.
konqueror	bookmarks	Add dependency on bookmark package.
kopete	addbookmarks	Automatically add incoming urls to bookmarks.
	autoreplace	Automatically replace selected text
	contactnotes	Enables writing personal notes for contacts.
	gadu	Enable the Gadu protocol handler.
	groupwise	Enable the Groupwise protocol handler.
	highlight	Allows you to specify highlights on specific events.
	history	Enables saving chat history.
	latex	Embed latex formatted text into messages.
	meanwhile	Enable the Sametime protocol handler.
	msn	Enable "Windows live messenger" protocol support.
	nowlistening	Shows song you currently listen to in your status/etc. Bindings for many players.
	otr	Allows crypting your chat (drugs and talking nonsense are considered as good alternatives ;]).
	pipes	Send messages to external pipe.
	privacy	Filter for incoming messages
	qq	enable support for the Chinese network protocol.
	skype	Enable Skype protocol handler (not fully functional yet).
	sms	Enable SMS sendinge functionality.
	statistics	Everybody loves statistic graphs, especially cake ones. ;]
	testbed	Enable the testbed protocol.
	texteffect	Various fancy text effects for your messages (don't ever consider writing us with this enabled ;]).
	translator	Translate incoming and outgoing messages.
	urlpicpreview	Enables in conversation pictures preview.
	webpresence	Show your status and some more information on web.
	winpopup	Enable pop-up messages sending on windows. (same as good old "net send" messages ;])
	yahoo	Enable yahoo protocol support.
	zeroconf	Enable Link-Local Messaging via the bonjour protocol.
korundum	akonadi	Compile bindings for Akonadi.
	kate	Compile bindings for KDE Advanced Text Editor.
	okular	Compile bindings for kde-base/okular.
ksnapshot	kipi	Support for the KDE Image Plugin Interface.
kstars	fits	Enable support for the FITS image format through cfitsio
kstars	indi	Enable support for Astronomical control library using libindi
kwin	gles	Enable support for GLES.
libplasmaclock	holidays	Include support for holidays in plasma calendar
marble	designer-plugin	Enable designer plugin
okular	chm	Enable support for Microsoft Compiled HTML Help files
	ebook	Add E-Book support
	ps	Add PostScript support
perlkde	akonadi	Compile bindings for Akonadi.
	attica	Compile bindings for dev-libs/libattica.
	kate	Compile bindings for KDE Advanced Text Editor.
	okular	Compile bindings for kde-base/okular.
perlqt	declarative	Compile bindings for x11-libs/qt-declarative.
	multimedia	Compile bindings for x11-libs/qt-multimedia.
	phonon	Compile bindings for Phonon.
	qimageblitz	Compile bindings for media-libs/qimageblitz.
	qscintilla	Compile bindings for x11-libs/qscintilla.
	qthelp	Compile bindings for QtHelp from x11-libs/qt-assistant.
	qwt	Compile bindings for x11-libs/qwt.
	webkit	Compile bindings for x11-libs/qt-webkit.
plasma-workspace	google-gadgets	Add google-gadgets support
	qalculate	Enable Qalculate runner using sci-libs/libqalculate
	rss	Enables building RSSNOW plasmoid (requires kde-base/kdepimlibs)
powerdevil	pm-utils	Adds support for suspend/resume the system through sys-power/pm-utils
pykde4	semantic-desktop	Enables Nepomuk and Soprano python language bindings
qtruby	declarative	Compile bindings for x11-libs/qt-declarative.
	phonon	Compile bindings for Phonon.
	qscintilla	Compile bindings for x11-libs/qscintilla.
	qwt	Compile bindings for x11-libs/qwt.
	webkit	Compile bindings for x11-libs/qt-webkit.
qyoto	phonon	Compile bindings for Phonon.
	qscintilla	Compile bindings for x11-libs/qscintilla.
	webkit	Compile bindings for x11-libs/qt-webkit.
smoke	akonadi	Compile bindings for Akonadi.
	attica	Compile bindings for dev-libs/libattica.
	declarative	Compile bindings for x11-libs/qt-declarative.
	kate	Compile bindings for KDE Advanced Text Editor.
	multimedia	Compile bindings for x11-libs/qt-multimedia.
	okular	Compile bindings for kde-base/okular.
	phonon	Compile bindings for Phonon.
	qimageblitz	Compile bindings for media-libs/qimageblitz.
	qscintilla	Compile bindings for x11-libs/qscintilla.
	qthelp	Compile bindings for QtHelp from x11-libs/qt-assistant.
	qwt	Compile bindings for x11-libs/qwt.
	webkit	Compile bindings for x11-libs/qt-webkit.
smokekde	akonadi	Compile bindings for Akonadi.
	attica	Compile bindings for dev-libs/libattica.
	kate	Compile bindings for KDE Advanced Text Editor.
	okular	Compile bindings for kde-base/okular.
smokeqt	declarative	Compile bindings for x11-libs/qt-declarative.
	multimedia	Compile bindings for x11-libs/qt-multimedia.
	phonon	Compile bindings for Phonon.
	qimageblitz	Compile bindings for media-libs/qimageblitz.
	qscintilla	Compile bindings for x11-libs/qscintilla.
	qthelp	Compile bindings for QtHelp from x11-libs/qt-assistant.
	qwt	Compile bindings for x11-libs/qwt.
	webkit	Compile bindings for x11-libs/qt-webkit.
solid	wicd	Enable Wicd wired and wireless network manager.
step	qalculate	Enable the libqalculate library for unit conversion

kde-misc

Package	Flag	Description
akonadi-google	oldpim	Allow the use of non-akonadi kdepim-4.4
kcm-grub2	hwinfo	Used to work out supported framebuffer resolutions
	imagemagick	Create splash images compatible with GRUB2
	packagekit	Add support for packagekit integration
krusader	bookmarks	Add dependency on bookmark package.
networkmanagement	consolekit	Enable support for sys-auth/consolekit
synaptiks	upower	Handle mouse devices correctly across suspend and resume with upower
tellico	addressbook	Add support for kdepim addressbook (kabc)

lxde-base

Package	Flag	Description
lxdm	consolekit	Enables support for authorization using consolekit
lxdm	gtk3	Use GTK+3 instead of 2

mail-client

Package	Flag	Description
alpine	chappa	enhance alpine by applying Eduardo Chappa's patches
	onlyalpine	installs only the alpine binary, so it does not collied with app-editors/pico and/or mail-client/pine
	passfile	Adds support for caching passwords into a file between sessions
	smime	Enable support for S/MIME
	topal	Enable support for net-mail/topal
balsa	crypt	Adds support for GnuPG encryption
	gtkspell	Use gtkspell for dictionary support
	rubrica	Adds support for app-office/rubrica addressbook
	webkit	Enable webkit based html renderer
claws-mail	bogofilter	Build mail-filter/bogofilter plugin
	dillo	Enables support for inline HTTP email viewing with a plugin (which depends on the www-client/dillo browser)
	smime	Build plugin for S/MIME support
	spamassassin	Build mail-filter/spamassassin plugin
	ssl	Use gnutls for Secure Socket Layer transactions (deprecated, USE=gnutls should be used)
evolution	clutter	Build with clutter support for animation effects
	connman	Enable net-misc/connman support (requires 'networkmanager' USE flag to be disabled).
	crypt	Enable GPG encryption support using app-crypt/gnupg and app-crypt/pinentry
	gnome-online-accounts	Enable using net-libs/gnome-online-accounts for authorization
	ldap	Enable support for fetching contacts from an LDAP or Active Directory server using net-nds/openldap
	map	Enable support for displaying contacts on a map inside evolution using media-libs/libchamplain
	networkmanager	Allows Evolution to automagically toggle online/offline mode by talking to net-misc/networkmanager and getting the current network state
mail-notification	gmail	Enable Gmail mailbox checking
	mh	Enable MH mailbox checking
	pop	Enable support for pop
	sylpheed	Enable support for MH mailboxes used by mail-client/sylpheed
mutt	gpg	Enable support for app-crypt/gpgme
	pop	Enable support for pop
	sidebar	Use the vanilla tree + sidebar patch
	smime	Enable support for smime
	smtp	Enable support for smtp
	tokyocabinet	Enable tokyocabinet database backend for header caching
nail	kerberos	If network is enabled, this adds support for GSSAPI login on IMAP through virtual/kerberos.
	net	Enable support for network protocols (POP, IMAP and SMTP). If you only need to send mail with the local Transport Agent, disabling this will get you support for only /usr/sbin/sendmail call.
	ssl	If network is enabled, this adds support for S/MIME and SSL/TLS-powered protocols through dev-libs/openssl.
pine	largeterminal	Add support for large terminals by doubling the size of pine's internal display buffer
pine	passfile	Adds support for caching IMAP passwords into a file between sessions
postler	ayatana	Enable Messaging Menu support via dev-libs/libindicate
squirrelmail	filter	Enable mail-filter/amavisd-new filtering
sylpheed	oniguruma	Use dev-libs/oniguruma for regular expression
thunderbird	bindist	Disable official Firefox branding (icons, name) which are not binary-redistributable according to upstream.
	crashreporter	Enable crash reporter for bugs
	crypt	Enable encryption support with enigmail
	custom-optimization	Enable user CFLAGS
	gconf	Enable gnome2 gconf support
	ipc	Use inter-process communication between tabs and plugins. Allows for greater stability in case of plugin crashes
	lightning	Enable calendar support
	mozdom	Enable Mozilla's DOM inspector
	system-sqlite	Use the system-wide dev-db/sqlite installation with secure-delete enabled
	webm	Use system media-libs/libvpx for HTML5 WebM video support.
thunderbird-bin	crashreporter	Enable crash reporter for bugs

mail-filter

Package	Flag	Description
amavisd-new	courier	Add courier support
	dkim	Add DomainKeys Identified Mail support
	qmail	Add qmail support
	razor	Add support for mail-filter/razor
	spamassassin	Add support for mail-filter/spamassassin
ask	procmail	Adds support for mail-filter/procmail
assp	spf	Adds support for Sender Policy Framework
assp	srs	Adds support for Sender Rewriting Scheme
bogofilter	tokyocabinet	Enable Tokyo Cabinet database support
clamassassin	clamd	Use the app-antivirus/clamav daemon for virus checking
clamassassin	subject-rewrite	Adds support for subject rewriting
dcc	rrdtool	Enable net-analyzer/rrdtool interface scripts
dkim-milter	diffheaders	On verification failure, compare the original and the received headers to look for possible munging
dovecot-antispam	crm114	Build CRM114 backend
	dspam	Build mail-filter/dspam backend
	mailtrain	Build mailtrain backend
	signature-log	Build signature-log backend
	spool2dir	Build spool directory backend
dspam	daemon	Enable support for DSPAM to run in --daemon mode
	debug	Enable debugging support (don't enable this unless something needs testing!)
	debug-bnr	Activates debugging output for Bayesian Noise Reduction
	debug-verbose	Cause DSPAM produce verbose debug output and write them into LOGDIR/dspam.debug file. Never enable this for production builds!
	domain-scale	Build for domain scale setups - puts data to $HOME/data/domain.com/user
	hash	Enable support for the file-orientated hash driver
	large-domain	Builds for large domain rather than for domain scale
	large-scale	Build for large scale setups - puts data to $HOME/data/u/s/user
	small-scale	Build for small scale setups - puts data to $HOME/data/user
	user-homedirs	uild with user homedir support
	virtual-users	Build with virtual-users support
libmilter	poll	Use poll instead of select
maildrop	authlib	Add courier-authlib support
maildrop	tools	Install maildirmake and deliverquota tools
mimedefang	poll	Use poll instead of select
opendkim	asyncdns	Use inbuilt asynchronous DNS library for queries
	ldap	Enable openldap as a dataset facilitator or keys, determining domains to sign for, and any other dataset that opendkim supports.
	lua	Enables control over signature verification, filtering and policy to be controlled by user defined lua scripts.
	opendbx	Use opendbx backend to facilitate dataset driven OpenDKIM configuration options like stats, bodylengthdb, etc. against a wide variety of database types
	poll	Use poll() instead of select() for the provided asynchronous resolver library.
	sasl	Used to authenticate to a LDAP server in various ways if required.
	unbound	Use the unbound dnssec library to perform DKIM DNS queries.
postgrey	targrey	Enables the targrey patch
qmail-scanner	spamassassin	Build faster mail-filter/spamassassin checks into qmail-scanner
spamassassin	qmail	Build qmail functionality and docs
spamassassin-fuzzyocr	amavis	Enable support for mail-filter/amavisd-new
	gocr	Enable support for the gocr OCR engine
	logrotate	Install support files for app-admin/logrotate
	ocrad	Enable support for the ocrad OCR engine
	tesseract	Enable support for the tesseract OCR engine
spamdyke	tls	Enables TLS protocol for spamdyke
zdkimfilter	debug	Log process and signal information. Also leave the child process running for gdb examination.
	mysql	MySQL client based statistics based storage.
	opendbx	An alternate statistics based storage engine.

mail-mta

Package	Flag	Description
courier	fax	Enables fax support in the courier mail server
	norewrite	Prevents courier mail server from mangling virtual user addresses when sending
	web	Enable the web interface
	webmail	Enable the webmail interface
exim	dcc	Adds support for Distributed Checksum Clearinghouse (DCC)
	dkim	Adds support for DomainKeys Identified Mail (DKIM)
	dnsdb	Adds support for a DNS search for a record whose domain name is the supplied query
	dovecot-sasl	Adds support for Dovecot's authentication
	dsn	Adds support for Delivery Status Notifications (DSN)
	exiscan-acl	Patch providing support for content scanning
	lmtp	Adds support for lmtp
	mbx	Adds support for UW's mbx format
	spf	Adds support for Sender Policy Framework
	srs	Adds support for Sender Rewriting Scheme
msmtp	mta	Enable this to install as system-wide MTA
netqmail	authcram	Enable AUTHCRAM support
	gencertdaily	Generate SSL certificates daily instead of hourly
	highvolume	Prepare netqmail for high volume servers
	noauthcram	If you do NOT want AUTHCRAM to be available
postfix	dovecot-sasl	Enable net-mail/dovecot protocol version 1 (server only) SASL implementation
	ldap-bind	Adds support for binding to LDAP backend using dev-libs/cyrus-sasl
	memcached	Adds support for using net-misc/memcached for lookup tables
	vda	Adds support for virtual delivery agent quota enforcing
qmail-ldap	cluster	Enable this if you want to have cluster support in qmail-ldap
	gencertdaily	Generate SSL certificates daily instead of hourly
	highvolume	Prepare qmail for high volume servers
	rfc2307	Add support for RFC2307 compliant uid/gid attributes
	rfc822	Add support for RFC822 compliant mail attributes
qpsmtpd	async	Add deps + support for asynchronous mail reception/processing as well as preforked daemon
qpsmtpd	postfix	create user with permissions for proper postfix interaction
ssmtp	maxsysuid	Allow to define a MinUserId
	md5sum	Enables MD5 summing for ssmtp
	mta	Install symlinks for sendmail-compatible MTA.

media-fonts

Package	Flag	Description
culmus	ancient	Install ancient semitic scripts
	fancy	Install fancy fonts
	fontforge	Use media-gfx/fontforge to build fonts from source
	taamey	Install taamey fonts
culmus-ancient	fontforge	Use media-gfx/fontforge to build fonts from source
dejavu	fontforge	Use media-gfx/fontforge to build fonts from source
intlfonts	bdf	Installs BDF fonts in addition to PCF
liberation-fonts	fontforge	Use media-gfx/fontforge to build fonts from source
montecarlo	bdf	Install BDF fonts in addition to PCF
mplus-outline-fonts	ipafont	Generates new fonts merged with media-fonts/ja-ipafonts
sil-charis	compact	Use more compactly spaced font
sil-gentium	compact	Also install more compact version of the font.
terminus-font	a-like-o	Changes view of letter 'a' - a looks like o (see homepage)
	bolddiag	Boldified diagonal parts of '4', 'k', 'x' and some other chars
	distinct-l	ll2 variant with more distinctive l (lowercase L)
	pcf	Install Portable Compiled Font (PCF) (required for X11)
	psf	Install PC Screen Font (PSF) with unicode data (for linux console)
	quote	Changes view of quotes: symmetric ` and ' instead of asymmetric one (see homepage)
	raw-font-data	Install RAW font data which should be compatible with most UNIX systems (you don't need this on linux)
	ru-dv	Changes view of Russian letters 'de' and 've' (see homepage)
	ru-g	Changes view of Russian letter 'ge' (see homepage)
	ru-i	Changes view of Russian letter 'i' - not like Latin u, but like "mirrored" N (see homepage)
	ru-k	Changes view of Russian letter 'k' (see homepage)
	width	Wider versions of some font elements

media-gfx

Package	Flag	Description
album	plugins	Install optional plugins
album	themes	Install optional themes
asymptote	boehm-gc	Enables using the Boehm-Demers-Weiser conservative garbage collector
asymptote	sigsegv	Enables using dev-libs/libsigsegv
blender	apidoc	Build GameEngine/Python/C API documentation directly from the source code using tools epydoc (dev-python/epydoc) and doxygen (app-doc/doxygen).
	blender-game	Adds Game Engine support to Blender (2.4* ebuilds).
	collada	Add support for Collada interchange format through media-libs/opencollada.
	contrib	Install contrib scripts.
	dds	Adds DDS textures support to Blender.
	elbeem	Adds surface fluid simulation to Blender using El'Beem library.
	game-engine	Adds Game Engine support to Blender (2.5* ebuilds).
	player	Build the Blender Player.
	redcode	This flag add support for RED CODE camera digital format (5K HD images *.r3d) - EXPERIMENTAL.
	tweak-mode	This flag allows you to model without confirming each translation, in particular it lets you grab with left mouse button (LMB) and not having to confirm by another click. Blender 'Tweak Mode' is similar to the 'Tweak Mode' of the Wings modeller (media-gfx/wings).
	verse	Adds verse clustering features to Blender.
brlcad	benchmarks	Run benchmarks during test phase (need test option enabled)
comix	rar	Pulls app-arch/unrar for rar file support
darktable	flickr	Add support for uploading photos to flickr
	opencl	Enable opencl support
	rawspeed	Enable the rawspeed backend
	slideshow	Build the opengl slideshow viewer
digikam	addressbook	Add support for kdepim
	linguas_ha	Hausa translation
	linguas_mi	Maori translation
	linguas_tt	?? translation
	linguas_ven	Venda translation
	themedesigner	Build the digikam theme designer
	thumbnails	Enable thumbnails database support
	video	Pull in mplayerthumbs to enable video thumbnails
enblend	gpu	GPU support for Enblend
enblend	image-cache	allow for processing of large images
eog	introspection	Use dev-libs/gobject-introspection for introspection
exact-image	swig	Adds Swig support dev-lang/swig
exiv2	contrib	Build additional contrib components
f-spot	flickr	Enable building of the Flickr exported.
fontforge	cjk	Controls whether fontforge understands the gb12345 encoding and installs cidmap package to edit CID-keyed fonts
	pango	Enable pango font rendering
	pasteafter	Controls whether fontforge has a paste after command (Useful for making words?). This is kind of fun, but it isn't useful for normal fonts.
	tilepath	Controls whether fontforge has a tile path command (a variant of expand stroke) This is useful for very decorative fonts, most people won't want it.
	truetype-debugger	Enable truetype debugger in fontforge
	type3	Build in support for type3/svg fonts containing multilayered drawing with strokes, fills, images, etc. Type3 fonts are only supported by postscript printers (not by most windowing displays). They are capable of more exotic images than normal fonts but require much more effort to support.
fotowall	webcam	Enable webcam support
freewrl	glew	Enable glew extensions
	java	Build and install java EAI/SAI support library
	libeai	Build EAI C library
	osc	Allows for OSC-based control and communication between multiple freewrl instances
gimp	smp	Enable support for multiprocessors
gimp	webkit	Enable the webkit rendering engine
gmic	graphicsmagick	Enable support for many common image file formats using the GraphicsMagick++ library
gmic	opencv	Enable support for webcams using the OpenCV library
graphicsmagick	fpx	Enable FlashPix support with media-libs/libfpx
	modules	Compile graphicsmagick with dynamically loadable modules
	q16	Set storage quantum size to 16 (~2*memory)
	q32	Set storage quantum size to 32 (~5*memory)
graphviz	lasi	Enables PostScript output via media-libs/lasi library
gthumb	http	Enable webservice integration through net-libs/libsoup
gthumb	slideshow	Enable slideshow plugin
hugin	sift	automatically align images with media-gfx/autopano-sift or media-gfx/autopano-sift-C
imagemagick	autotrace	Use media-gfx/autotrace to convert bitmaps into vector graphics
	corefonts	Use media-fonts/corefonts which is required by some commands
	fpx	Enable media-libs/libfpx support
	gs	Enable ghostscript support
	hdri	enable High Dynamic Range Images formats
	lqr	Enable experimental liquid rescale support using media-libs/liblqr
	opencl	Enable OpenCL support
	pango	Enable Pango support using x11-libs/pango
	q32	Set quantum depth value to 32
	q64	Set quantum depth value to 64
	q8	Set quantum depth value to 8
	webp	Enable webp image format support using media-libs/libwebp
imageworsener	webp	enable webp image format support
inkscape	dia	pull in app-office/dia for dia import extension
	gs	enables support for the PostScript import extension
	inkjar	enables support for OpenOffice.org SVG jar files
iscan-plugin-gt-f500	minimal	Install the firmware only, and not the plugin.
jpeg2ps	metric	Default to A4 paper size
k3d	3ds	Enable support for 3D Studio models
	cuda	Use nvidia cuda toolkit for speeding up computations
	gts	Add Support for the GNU Triangulated Surface Library sci-libs/gts
kphotoalbum	geolocation	Add support for kde-base/marble
kphotoalbum	kipi	Support for the KDE Image Plugin Interface
nip2	goffice	use x11-libs/goffice to show plots
openclipart	gzip	Compresses clip art using gzip
potrace	metric	default to a4 paper size and metric measurement
povray	mkl	Enable support for Intel Vector Math Library, part of sci-libs/mkl
pstoedit	emf	Enable media-libs/libemf support
pstoedit	flash	Enable media-libs/ming SWF support
splashutils	fbcondecor	Support for the fbcondecor kernel patch.
ufraw	contrast	enable contrast setting option
	fits	Enable support for the FITS image format through sci-libs/cfitsio
	timezone	enable DST correction for file timestamps
xsane	ocr	Enable support for Optical Character Recognition reader
yafaray	blender	install media-gfx/blender scripts

media-libs

Package	Flag	Description
a52dec	djbfft	Prefer D.J. Bernstein's library for fourier transforms
allegro	dumb	Enable media-libs/dumb module library support
	physfs	Enable physfs support
	vga	Enables the VGA graphics driver
alsa-lib	alisp	Enable support for ALISP (ALSA LISP) interpreter for advanced features.
alure	dumb	Enable media-libs/dumb module library support
alure	fluidsynth	Enables Fluidsynth MIDI software synthesis
babl	introspection	Use dev-libs/gobject-introspection for introspection
babl	vala	Enable bindings for dev-lang/vala
cal3d	16bit-indices	Enables use of 16bit indices
chromaprint	tools	Build and install fpcalc and fpcollect tools
clutter	gtk	Use gdk-pixbuf from x11-libs/gtk+ as image rendering backend
clutter	introspection	Use dev-libs/gobject-introspection for introspection
clutter-gst	introspection	Use dev-libs/gobject-introspection for introspection
clutter-gtk	introspection	Use dev-libs/gobject-introspection for introspection
cogl	introspection	Use dev-libs/gobject-introspection for introspection
cogl	pango	Build cogl-pango library for x11-libs/pango integration
coin	simage	Texture loading via media-libs/simage library
devil	allegro	Add support for Allegro
edje	cache	Enable caching
esdl	image	Enable image support
evas	cache	Enable experimental caching to speed up rendering
	eet	Support dev-libs/eet
	gles	Enable gles falvor of gl instead of standard
faad2	digitalradio	Digital Radio Mondiale (warning: disables other decoders)
ffmpegsource	postproc	Enables image post-processing via libpostproc (part of FFmpeg).
flickcurl	raptor	Use media-libs/raptor for proper RDF serializing
freeglut	mpx	Enable support for multi-pointer-X. One pointer for each pointer device.
freetype	auto-hinter	Use the unpatented auto-hinter instead of the (recommended) TrueType bytecode interpreter
	bzip2	Support bzip2 compressed PCF fonts.
	fontforge	Install internal headers required for TrueType debugger in media-gfx/fontforge (built with USE=truetype-debugger)
	kpathsea	Enable TeX support (ttf2pk and ttf2pfb)
	utils	Install utilities and examples from ft2demos
freeverb3	audacious	Build Audacious plugin
	avx	Adds support for Advanced Vector Extensions instructions
	forcefpu	Disable assembly code
	plugdouble	Build plugins in double precision mode (default is float)
	sse3	Enable SSE3 support
	sse4	Enable SSE4 support
gegl	introspection	Use dev-libs/gobject-introspection for introspection.
	lensfun	Enable support for media-libs/lensfun.
	umfpack	Enable sparse solving via sci-libs/umfpack.
	vala	Enable bindings for dev-lang/vala
giflib	rle	Build converters for RLE format (utah raster toolkit)
gmtk	dconf	Enable support for gnome-base/dconf
grilo	introspection	Use dev-libs/gobject-introspection for introspection
	network	Enable network access for media discovery using net-libs/libsoup
	test-ui	Build and install a test UI for the library
	vala	Generate bindings for dev-lang/vala
gst-plugins-bad	orc	Use dev-lang/orc for runtime optimisations
gst-plugins-base	introspection	Use dev-libs/gobject-introspection for introspection
gst-plugins-base	orc	Use dev-lang/orc for runtime optimisations
gst-plugins-good	orc	Use dev-lang/orc for runtime optimisations
gst-rtsp-server	introspection	Use dev-libs/gobject-introspection for introspection
gst-rtsp-server	vala	Add support for dev-lang/vala
gstreamer	introspection	Use dev-libs/gobject-introspection for introspection
gupnp-dlna	introspection	Use dev-libs/gobject-introspection for introspection
harfbuzz	glib	Enable support for C library routines from dev-libs/glib
harfbuzz	graphite	Enable support for non-Roman fonts via media-gfx/graphite2
libass	enca	Enables support for charset discovery and conversion.
libass	harfbuzz	Enables OpenType shaping via media-libs/harfbuzz.
libbluray	aacs	Add support for decryption of AACS
	java	Add support for BD-J
	utils	Install command-line utilities and examples
	xine	Build Blu-ray input plugin for Xine
libcanberra	alsa	Enables ALSA sound driver.
	gstreamer	Enables gstreamer sound driver. Not useful when alsa or pulseaudio is available.
	gtk	Enables building of gtk+ helper library, gtk+ runtime sound effects and the canberra-gtk-play utility. To enable the gtk+ sound effects add canberra-gtk-module to the colon separated list of modules in the GTK_MODULES environment variable.
	gtk3	Enables building of gtk+3 helper library, gtk+3 runtime sound effects and the canberra-gtk-play utility. To enable the gtk+3 sound effects add canberra-gtk-module to the colon separated list of modules in the GTK_MODULES environment variable.
	pulseaudio	Enables PulseAudio sound driver that should be able to support positional event sounds. This is the preferred choice for best sound events experience and picked by default if compiled in and possible to use at runtime.
	sound	Install x11-themes/sound-theme-freedesktop to get sounds on Gnome and Xfce.
	tdb	Enables Trivial Database support for caching purposes.
libchamplain	html	Install gtk-doc html version for this package
	introspection	Use dev-libs/gobject-introspection for introspection
	vala	Generate bindings for dev-lang/vala
libggi	vis	Enables sparc vis support for libggi
libgnome-media-profiles	twolame	Allow encoding MPEG Audio Layer 2 (MP2) files using twolame
libgpod	gtk	Enable ArtworkDB support
libmikmod	raw	Enable raw file writer plug-in
libmp4v2	utils	Install command-line utilities
libpng	apng	support unofficial APNG (Animated PNG) spec
libquicktime	schroedinger	Enable Dirac video support (an advanced royalty-free video compression format) via libschroedinger (high-speed implementation in C of the Dirac codec).
libraw	demosaic	Enable support for external interpolation algorithms
libsdl	audio	Control audio support (disable at your own risk)
	joystick	Control joystick support (disable at your own risk)
	ps3	Build the PS3 video driver
	tslib	Build with tslib support for touchscreen devices
	video	Control video support (disable at your own risk)
libvpx	postproc	Enable additional post processing filters
	sse3	Enable optimization for SSE3 capable chips
	sse4_1	Enable optimization for SSE4_1 capable processors (Intel Core 2 Penryn and later chips)
	ssse3	faster floating point optimization for SSSE3 capable chips (Intel Core 2 and later chips)
mash	introspection	Use dev-libs/gobject-introspection for introspection
mediastreamer	amr	Use of AMR Narrow Band codec plugin
	ilbc	Use of iLBC (RFC3951) codec plugin
	video	Enable video support
memphis	introspection	Use dev-libs/gobject-introspection for introspection
memphis	vala	Add support for Vala
mesa	classic	Build drivers based on the classic architecture.
	egl	Enable EGL support.
	gallium	Build drivers based on Gallium3D, the new architecture for 3D graphics drivers.
	gbm	Enable the Graphics Buffer Manager for EGL on KMS.
	gles	Enable GLES support.
	llvm	Enable LLVM backend for Gallium3D.
	openvg	Enable the OpenVG 2D acceleration API for Gallium3D.
	osmesa	Build the Mesa library for off-screen rendering.
	pax_kernel	Enable if the user plans to run the package under a pax enabled hardened kernel
	pic	disable optimized assembly code that is not PIC friendly
	shared-dricore	Enable sharing of common code for classic DRI drivers.
	shared-glapi	Enable sharing of common code for the OpenGL API.
mlt	compressed-lumas	Compress the luma files in png.
	frei0r	Build the module for media-plugins/frei0r-plugins
	lua	Build SWIG bindings for Lua
	melt	Build the melt commandline tool
	python	Build SWIG bindings for Python
	ruby	Build SWIG bindings for Ruby
	vdpau	Build with vdpau support
netpbm	rle	Build converters for the RLE format (utah raster toolkit)
opencv	cuda	Enable NVIDIA Cuda computations support
	eigen	Enable usage of dev-cpp/eigen for computations
	ipp	Enable Intel Integrated Primitive support
	sse3	Enable optimization for SSE3 capable chips
	ssse3	faster floating point optimization for SSSE3 capable chips (Intel Core 2 and later chips)
phonon	vlc	Install VLC Phonon backend
phonon	zeitgeist	Add support for Zeitgeist event tracking system
phonon-gstreamer	network	Enable network streaming support via libsoup
raptor	json	Enable support for JSON parsing
sdif	ftruncate	Enables usage of ftruncate v. truncate
sdl-image	webp	support loading WEBP images
sdl-mixer	fluidsynth	Use media-sound/fluidsynth for MIDI support
	midi	basic support for MIDI files
	playtools	Install playwave and playmus tools (useful for testing)
	wav	support WAVE files
sdl-sound	physfs	Enable physfs support
sge	image	enable sdl-image support
silgraphite	pango	Enables the pango-graphite pango module.
spandsp	fixed-point	Enable fixed point support
	sse3	Enable SSE3 support
	sse4	Enable SSE4 support
	sse4a	Enable SSE4a support
	sse5	Enable SSE5 support
svgalib	kernel-helper	Build the helper kernel module
swfdec	alsa	Use ALSA for audio output
	doc	Build documentation
	ffmpeg	Use media-plugins/gst-plugins-ffmpeg to enable Flash video support. Necessary if you want to use sites like youtube
	gstreamer	Enable media-libs/gstreamer to support various media input formats. i.e. audio (mp3) and video (flv)
	gtk	Enable GTK+ convenience library while is necessary for all GTK+ apps using swfdec (gnome-extra/swfdec-gnome and www-plugins/swfdec-mozilla)
	pulseaudio	Use media-sound/pulseaudio for audio output
taglib	asf	Provide support for Microsoft's 'advanced systems format' media container.
urt	gs	Add support for postscript
vips	fits	Enable support for the FITS image format through sci-libs/cfitsio
vips	orc	Use dev-lang/orc for runtime optimisations
win32codecs	real	Installs the real video codecs
x264	10bit	Set output bit depth to 10, this may not be compatible with all decoders
	interlaced	enable interlaced encoding support, this can decrease encoding speed by up to 2%
	pic	disable optimized assembly code that is not PIC friendly
xine-lib	bluray	Enable playback of Blu-ray filesystems using media-libs/libbluray
	dxr3	Enable support for DXR3 mpeg acceleration cards.
	flac	Build the media-libs/flac based FLAC demuxer and decoder. This flag is not needed for playing FLAC content, neither standalone nor in Ogg container (OggFLAC), but might have better support for exotic features like 24-bit samples or 96kHz sample rates.
	fusion	Enable support for the Fusion audio sub system
	gtk	Build the gdkpixbuf-based image decoder plugin.
	imagemagick	Build the ImageMagick-based image decoder plugin.
	mad	Build the media-libs/libmad based mp3 decoder. This mp3 decoder has superior support compared to the one coming from FFmpeg that is used as a fallback. If you experience any bad behaviour with mp3 files (skipping, distorted sound) make sure you enabled this USE flag.
	mmap	Use mmap() function while reading file from local disks. Using mmap() will use more virtual memory space, but leaves to the Kernel the task of caching the file's data. mmap() access should be faster, but might misbehave if the device where the file resides in is removed during playback.
	real	Enable support for loading and using RealPlayer binary codecs on x86 and amd64 Linux. Enabling this USE flag might make the package non-redistributable in binary form.
	truetype	Use media-libs/freetype for font rendering and media-libs/fontconfig for font discovery. Enabling this USE flag will allow OSD (such as subtitles) to use more advanced font and to more easily select which font to use. The support for TrueType fonts in xine-lib is still experimental, and might not be as good looking as the bitmap fonts used with this USE flag disabled.
	vdpau	Enables VDPAU decoders (requires nVidia video cards to offload CPU processing to video card
	vdr	Build the VDR plugin
	vidix	Enable support for vidix video output.
	vis	Adds support for SIMD optimizations for UltraSPARC processors.
	win32codecs	Enable support for loading and using Windows 32-bit binary codecs on x86 Linux and FreeBSD. Enabling this USE flag might make the package non-redistributable in binary form.
	xvmc	Enable support for XVideo Motion Compensation (accelerated mpeg playback).
xvid	pic	disable optimized assembly code that is not PIC friendly

media-plugins

Package	Flag	Description
audacious-plugins	adplug	Build with AdPlug (Adlib sound card emulation) support
	bs2b	Enable Bauer Bauer stereophonic-to-binaural headphone filter
	cue	Support CUE sheets using the libcue library
	fluidsynth	Support FluidSynth as MIDI synth backend
	gtk3	Link against version 3 of the GIMP Toolkit instead of version 2 (x11-libs/gtk+)
	midi	Build with amidi-plug (MIDI synth) support
	scrobbler	Build with scrobbler/LastFM submission support
	sid	Build with SID (Commodore 64 Audio) support
banshee-community-extensions	lastfmfingerprint	Enable support to ientify your music automatically, using the Last.fm online service.
	lirc	Enable the remote control plugin (uses app-misc/lirc)
	lyrics	Enable support for automatically fetching lyrics
	mirage	Enable the Mirage plugin which automatically, and intelligently generates playlists for you
	telepathy	Enables the Telepathy plugin which lets you to share and stream music with IM buddies
frei0r-plugins	facedetect	Enables building of facedetect plugin, which depends on media-libs/opencv
frei0r-plugins	scale0tilt	Enables building of scale0tilt and vectorscope plugins, which depend on media-libs/gavl
gkrellmpc	threads	Use separate thread to init connection (unsafe)
grilo-plugins	tracker	Build support for content discovery using the app-misc/tracker indexer
	upnp	Build support for UPnP devices using net-libs/gupnp and net-libs/gupnp-av
	vimeo	Build support for Vimeo content discovery using net-libs/libsoup and dev-libs/libgcrypt
	youtube	Build support for YouTube content discovery using dev-libs/libgdata
gst-plugins-a52dec	orc	Use dev-lang/orc for runtime detection of CPU MMX/MMXEXT/3dNow! capabilities to pass down to a52dec library.
gst-plugins-dts	orc	Use dev-lang/orc for runtime optimisations
gst-plugins-ffmpeg	orc	Use dev-lang/orc for runtime optimisations
gst-plugins-meta	http	Enable http streaming via net-libs/libsoup
	libvisual	Enable visualization effects via media-libs/libvisual
	mythtv	Support for retrieval from media-tv/mythtv backend
	vpx	Enables vp8 codec support using libvpx, required to play some HTML5 videos
kipi-plugins	expoblending	Build the expoblending plugin, which requires media-gfx/hugin
	gpssync	Build the gpssync plugin, which requires media-lib/libkgeomap and thereby marble
	linguas_ha	Hausa translation
	linguas_mi	Maori translation
	linguas_tt	?? translation
	linguas_ven	Venda translation
	mediawiki	Build the mediawiki export plugin
	mjpeg	Add mjpeg suppport
	panorama	Pull in dependencies needed by panorama plugin
	redeyes	Add redeyes removal suppport
	vkontakte	Build plugin for vkontakte.ru
mediastreamer-ilbc	20ms-frames	enable 20ms frame size (default is 30ms). Some VOIP providers such as Gizmo5 (aka Sipphone) require the codec to be compiled with the 30ms setting.
mythmusic	libvisual	Enables media-libs/libvisual support for effects
mythvideo	jamu	Use and configure the Just Another Metadata Utility by default
vdr-burn	dvdarchive	DMH DVD - Archive
vdr-burn	projectx	Enables support for media-video/projectx
vdr-dvdconvert	projectx	Enable support for media-video/projectx
vdr-epgsearch	tre	Add support for unlimited fuzzy searching with help of dev-libs/tre library
vdr-graphtft	graphtft-fe	Install external x11 remote frontend
	theme_avp	graphTFT Alien vs. Predato theme
	theme_deepblue	graphTFT default theme
	theme_deeppurple	graphTFT Deep Purple theme
	theme_poetter	graphTFT Poetter theme
	touchscreen	Enable Touchscreen support
vdr-music	4mb-mod	Enables support for modded FF-Card to 4MB ram or softdecoder
	ff-card	Enables scrollmode on FF-Card
	graphtft	Enable support for media-plugins/vdr-graphtft
	hd	Support for HighDefinition OSD on softdecoder( e.g xineliboutput, vdpau, ehd )
vdr-pvr350	yaepg	Enables full support for the output format of media-plugins/vdr-yaepg
vdr-softdevice	mmxext	enables MMXExt support
vdr-streamdev	client	Compile the VDR plugin vdr-streamdev-client that acts like a dvb-budget card
vdr-streamdev	server	Compile the VDR plugin vdr-streamdev-server that allows remote systems to access the DVB cards used for the local VDR
vdr-text2skin	contrib	Install user contributed scripts
vdr-weatherng	dxr3	enables lower osd color depth for dxr3 cards
vdr-xine	yaepg	Enables support for the plugin vdr-yaepg (showing scaled video besides OSD)
vdr-xineliboutput	libextractor	Use media-libs/libextract to gather files' metadata in media-player
	vdpau	Enables VDPAU support (requires nVidia video cards) to offload MPEG2/MPEG4/VC1/WMV CPU processing to video card
	vdr	Compile the vdr output plugin to use local or remote xine as output
	xine	Compile the xine input plugin for displaying vdr video and OSD

media-radio

Package	Flag	Description
ax25-tools	X	Enable some X based configuration tools.
fldigi	hamlib	Enables support by the Hamlib amateur radio rig control library to get/set frequency and mode of the ham radio in use
tucnak2	ftdi	Enable support for FTDI USB chips
tucnak2	hamlib	Enables support by the Hamlib amateur radio rig control library to get/set frequency and mode of the ham radio
unixcw	ncurses	Enables building the curses based morse code tutor program 'cwcp'.
xastir	festival	Enable text to speech synthesizer
	gdal	Support for some further map formats
	geotiff	Install geotiff support. Allows using USGS DRG topo maps or other types of geotiff mapes/images
	graphicsmagick	Use graphicsmagick instead imagemagick for rendering

media-sound

Package	Flag	Description
abcde	id3	Support ID3, ID3v2 tagging of audio files
	normalize	Add support for normalizing audio file volume levels
	replaygain	Support for Replay Gain metadata, for relative volume adjustment
abcm2ps	pango	Use the pango library to render fonts with non-latin characters
alsaplayer	id3tag	Enables ID3 tagging with id3tag library
amarok	daap	Enable the scripts for music sharing through DAAP. This flag adds dependencies on www-servers/mongrel to allow sharing of the Amarok music collection through DAAP protocol. Please note that turning this flag off has no effect on DAAP browsing.
	embedded	Use libmysqld, MySQL embedded server library. Try disabling this if you encounter -PIC related in amarok, it will make amarok rely only on standalone MySQL server.
	lastfm	Enable Last.fm streaming services support through media-libs/liblastfm
	mp3tunes	Enable mp3tunes integration
	ofa	Use media-libs/libofa to compute MusicDNS acoustic fingerprints (used by MusicBrainz)
	playdar	Build the playdar collection
	player	Build the player
	upnp	Support for upnp servers
	utils	Build the utils - old media-sound/amarok-utils
aqualung	ifp	Enable support for iRiver iFP portable audio players
	lua	Enable support for programmable title formatting with dev-lang/lua
	mac	Enable support for decoding Monkey's Audio files
	podcast	Enable podcast support
	systray	Enable system tray support
ardour	lv2	Add support for Ladspa V2
ario	audioscrobbler	Enable song tracking via last.fm
ario	idle	Enable experimental support for MPD's idle command to reduce bandwidth and cpu usage, requires MPD 0.14
audacious	chardet	Try to handle non-UTF8 chinese/japanese/korean ID3 tags
audacious	gtk3	Link against version 3 of the GIMP Toolkit instead of version 2 (x11-libs/gtk+)
audacity	id3tag	Enables ID3 tagging with id3tag library
	midi	Enables MIDI support
	soundtouch	Enables soundtouch library support
	twolame	Enables twolame support (MPEG Audio Layer 2 encoder)
	vamp	Enables vamp plugins support (Audio analysing plugins)
banshee	boo	Use external Boo instead of the bundled one
	bpm	Build beats per minute detection extension
	cdda	Build with audio CD support
	daap	Build with Daap support
	karma	Build with karma support
	web	Enable support for plugins that access web-based services such as Amazon and wikipedia (requires net-libs/webkit-gtk)
	youtube	Enable the Youtube plugin
clementine	ayatana	Build in support for Ayatana notification using the libindicate-qt plugin.
	kde	Enable plasma krunner global search
	lastfm	Enable Last.fm streaming services support through media-libs/liblastfm
	ofa	Support for Open Fingerprint Architecture (OFA)
	projectm	Build with ProjectM visualization
	wiimote	Enable support for Wii remote
cmus	pidgin	install support script for net-im/pidgin
cmus	wma	add support for Windows Media Audio
darkice	twolame	Build with twolame support
decibel-audio-player	gnome	Adds Gnome media keys support, so you can control Decibel using hotkeys.
decibel-audio-player	gnome-keyring	Adds support for storing your Last.fm password using gnome-keyring.
denemo	fluidsynth	Enable Fluidsynth MIDI software synthesis
dir2ogg	mac	Add support for decoding Monkey's Audio files
dir2ogg	wma	Add support for wma files through mplayer
ecasound	oil	Use dev-libs/liboil for inner loop optimizations
fapg	xspf	Enable support for saving XSPF playlists.
flacon	mac	Add support for Monkey's Audio files
	replaygain	Support for Replay Gain metadata, for relative volume adjustment
	tta	Add support for True Audio encoding
freewheeling	fluidsynth	compile with support for fluidsynth
gejengel	audioscrobbler	Enable track submission on last.fm
gimmix	cover	Enable cover art fetching
gimmix	lyrics	Enable lyric fetching
gmpc	unique	Enable single instance support using dev-libs/libunique
gmpc	xspf	Enable support for reading and saving XSPF playlists
gmusicbrowser	webkit	Enable GTK+ based WebKit support
google-musicmanager	log	Enables advanced logging through dev-libs/log4cxx
gpodder	webkit	Enable the webkit rendering engine for HTML episode shownotes
guayadeque	ayatana	Build in support for Ayatana notification using the libindicate plugin.
herrie	http	Enable http streaming
herrie	xspf	Enable support for reading and saving XSPF playlists
hydrogen	archive	Use libarchive instead of libtar
jack-audio-connection-kit	coreaudio	Build the CoreAudio driver on Mac OS X systems
	cpudetection	Enables runtime cpudetection
	netjack	Build with support for Realtime Audio Transport over generic IP
	pam	Add basic realime configuration via sys-auth/realtime-base
lame	mp3rtp	Build the mp3-to-RTP streaming utility. UNSUPPORTED
lmms	fluidsynth	Enables Fluidsynth MIDI software synthesis plugin.
	stk	Enables STK Mallet plugin.
	vst	Enables the VeSTige plugin to run VST plugins through Wine.
mangler	celt	High quality, low delay audio codec
	espeak	Text to speach engine
	g15	Logitech g15 lcd support
moc	sid	Build with SID (Commodore 64 Audio) support
mp3blaster	sid	Build with SID (Commodore 64 Audio) support
mp3splt-gtk	audacious	Include media-sound/audacious support
mp3splt-gtk	gtk3	Link against x11-libs/gtk+:3 instead of x11-libs/gtk+:2
mpd	cdio	Use libcdio for ISO9660 parsing support
	cue	Support CUE Sheet Parser Library
	curl	Support for web stream listening
	fifo	Support writing audio to a FIFO
	fluidsynth	Enables Fluidsynth MIDI software synthesis
	id3tag	Support for ID3 tags
	inotify	Use the Linux kernel inotify subsystem to notice changes to mpd music library
	lame	Support for MP3 streaming via Icecast2
	lastfmradio	Support listening to last.fm radio stations
	mpg123	Enable support for mp3 decoding over media-sound/mpg123
	network	Enables network streaming support
	pipe	Support writing audio to a pipe
	sid	Build with SID (Commodore 64 Audio) support
	twolame	Support twolame MPEG-2 encoding
	wildmidi	Enable MIDI support via wildmidi
	zip	Support for ZIP files
mpfc	wav	Enable wav audio codec support
mpg123	3dnowext	Enable 3dnowext cpu instructions
mumble	g15	Enable support for the Logitech G15 LCD (and compatible devices).
mumble	speech	Enable text-to-speech support in Mumble.
murmur	ice	Use dev-cpp/Ice to enable remote control capabilities.
ncmpc	artist-screen	Enable artist screen
	colors	Enable color support
	help-screen	Enable the help screen
	key-screen	Enable key editor screen
	lyrics-screen	Enable lyrics screen
	mouse	Enable curses getmouse support
	search-screen	Enable search screen
	song-screen	Enable song viewer screen
ncmpcpp	clock	Enable clock screen
	fftw	Build the visualizer plugin that pulls in sci-libs/fftw
	outputs	Enable outputs screen
	visualizer	Enable visualizer screen with sound wave/frequency spectrum modes
pavucontrol	gtk3	Build against GTK+ 3 rather than 2 (which is the default).
pianobooster	fluidsynth	Enable Fluidsynth MIDI software synthesis
picard	coverart	Install plugin for direct coverart dowload
pms	regex	Enable regular expression searches using dev-libs/boost
podcatcher	bittorrent	Enable support for bittorrent downloads
pragha	glyr	Enable music metadata searchengine support using media-libs/glyr
pragha	lastfm	Enable last.fm support using media-libs/libclastfm
puddletag	cover	Enables editing of FLAC cover art
	musicbrainz	Enables support for musicbrainz, needs dev-python/python-musicbrainz
	quodlibet	Enables support for editing media-sound/quodlibet databases
pulseaudio	X	Build the X11 publish module to export PulseAudio information through X11 protocol for clients to make use. Don't enable this flag if you want to use a system wide instance. If unsure, enable this flag.
	asyncns	Use libasyncns for asynchronous name resolution.
	doc	Build the doxygen-described API documentation.
	equalizer	Enable the equalizer module (requires sci-libs/fftw).
	glib	Add support to dev-libs/glib-based mainloop for the libpulse client library, to allow using libpulse on glib-based programs.
	gnome	Use GConf to store user preferences on streams and so on. Don't enable this flag if you want to use a system wide instance. If unsure, enable this flag.
	orc	Use dev-lang/orc for runtime optimisations.
	oss	Enable OSS sink/source (output/input). Deprecated, upstream does not support this on systems where other sink/source systems are available (i.e.: Linux). The padsp wrapper is now always build if the system supports OSS at all.
	realtime	Makes PulseAudio use RealtimeKit (sys-auth/rtkit) to get real-time priority while running.
	system-wide	Allow preparation and installation of the system-wide init script for PulseAudio. Since this support is only supported for embedded situations, do not enable without reading the upstream instructions at http://pulseaudio.org/wiki/WhatIsWrongWithSystemMode .
qmmp	bs2b	Enable Bauer stereophonic-to-binaural headphone filter
	cover	Enable album cover support
	crossfade	Enable crossfade effect when switching tracks
	enca	Detects the character encoding automatically
	game	Enable Game music support
	kde	Use kde4 notifier system
	lyrics	Fetch track lyrics from the web
	midi	Enable midi support using wildmidi library
	mpris	Enable MPRIS support
	notifier	Enable qmmps' notifier system
	projectm	Enable projectm music visualization plugin
	scrobbler	Enable audioscrobbler/last.fm support
	stereo	Enable stereo effect
	tray	Build tray icon
qsampler	libgig	Enable libgig support for loading Gigasampler files and DLS (Downloadable Sounds) Level 1/2 files
qtractor	dssi	Enable support for DSSI Soft Synth Interface
	rubberband	Enable support for in-place audio clip pitch-shifting through the rubberband library
	suil	Enable LV2 Plug-in UI instantiation support via media-libs/suil.
qtscrobbler	cli	Build commandline client
rezound	16bittmp	Use 16bit temporary files (default 32bit float), useful for slower computers
rezound	soundtouch	compile with support for soundtouch
rhythmbox	clutter	Build the visualizer plugin which uses media-libs/clutter and x11-libs/mx
	daap	Build the local network music sharing plugin which uses the DAAP protocol using net-libs/libdmapsharing
	dbus	Allow the im-status plugin to set the status of your IM clients using dev-python/dbus-python
	html	Use net-libs/webkit-gtk for detecting and displaying HTML podcast episode descriptions.
	lastfm	Build a plugin for Last.fm and Librefm scrobbling
	udev	Enable hardware detection via sys-fs/udev replacing the deprecated sys-apps/hal code
	upnp	Build a plugin for local network music sharing which uses UPnP protocols using media-video/coherence, dev-python/louie, and dev-python/twisted
	webkit	Enable context panel plugin
rubyripper	cdrdao	Add support for advanced toc scanning using app-cdr/cdrdao
	cli	Build command line interface rubyripper
	normalize	Add support for normalizing audio file volume levels
	wav	Add support for wavegain
shntool	alac	Add support for Apple Lossless Audio Codec files
shntool	mac	Add support for Monkey's Audio files
snd	s7	Enable the s7 extension language (a version of Scheme)
sonata	lyrics	Support for lyrics fetching
sonata	trayicon	Enable support for trayicon
sonic-visualiser	id3tag	Enables ID3 tagging with id3tag library
sox	amr	Enables Adaptive Multi-Rate Audio support
sox	id3tag	Enables ID3 tagging with id3tag library
split2flac	enca	Try to guess the charset using enca
	flake	Add support for Flake, alternative FLAC encoder
	mac	Add support for Monkey's Audio files
	replaygain	Support for Replay Gain metadata, for relative volume adjustment
squeezeboxserver	aac	Enable playback support for AAC (.m4a) encoded files
squeezeslave	display	Enable a text-based display
	wma	Enable support for streaming Windows Media Audio
	zones	Pairs surround sound speakers into stereo zones (requires 5.1 setup or better)
tomahawk	resolver	Resolver download and installation integration
tomahawk	twitter	Enable twitter support
traverso	lv2	Add support for Ladspa V2
vorbis-tools	kate	Adds support for Ogg Kate subtitles via libkate.
vorbis-tools	ogg123	Build ogg123 player, needs libao and curl
xmms2	airplay	Support for airplay format
	asf	Support for Monkey's Audio (APE) format with help of bundled libasf
	gvfs	Transport for glibs virtual filesystem
	ices	Icecast source output plugin
	mac	Support for Monkey's Audio (APE) format with help of media-sound/mac
	mlib-update	Enable building of xmms2-mlib-updater client
	ofa	Support for Open Fingerprint Architecture (OFA)
	phonehome	This client sends anonymous usage-statistics to the xmms2
	server	Build xmms2 player daemon (otherwise only clients are built)
	sid	Support for C64 SID
	vocoder	Phase vocoder effect plugin
	xml	Enable support for various XML based playlists and sources: RSS, XSPF
xmp	audacious	Enable audacious support
xnoise	lastfm	Enable support for lastfm cover art fetching and scrobbling
xnoise	lyrics	Enable support for lyrics fetching
xwax	alsa	Adds support for ALSA audio input/output.
	cdda	Sets runtime dependencies to support decoding audio from a compact disc.
	fallback	Sets runtime dependencies to support decoding "other" audio files.
	mp3	Sets runtime dependencies to support decoding MP3 audio.
	xwax_decoders_aac	Sets runtime dependencies to support decoding AAC audio.
	xwax_decoders_cd	Sets runtime dependencies to support decoding audio from a compact disc.
	xwax_decoders_flac	Sets runtime dependencies to support decoding FLAC audio.
	xwax_decoders_misc	Sets runtime dependencies to support decoding "other" audio files.
	xwax_decoders_mp3	Sets runtime dependencies to support decoding MP3 audio.
	xwax_decoders_ogg	Sets runtime dependencies to support decoding Ogg Vorbis audio.

media-tv

Package	Flag	Description
freevo	ivtv	Enables ivtv support
	mixer	Enable support for adjusting volume via media-sound/aumix
	tv	Enable support for the tv guide plugin
	tvtime	Enables tvtime support, additional to tv use flag
gentoo-vdr-scripts	nvram	Add support for using nvram-wakeup to set wakeup time in bios
mythtv	alsa	Allows MythTV to directly output sound to ALSA devices, this is needed if you are using ALSA dmix or SPDIF. Note, you will have to physically type your device into the MythTV configuration since it will only give you /dev/dsp devices in the drop down.
	altivec	Builds ffmpeg's codec libraries with altivec support.
	autostart	Uses a custom autostart configuration gleaned from experience with MythTV since its early versions and discussed with other MythTV maintainers and users. Does not rely on KDE being installed like most methods do.
	bluray	Pulls in libbluray for BluRay support.
	debug	Instructs Qt to use the 'debug' target instead of 'release' target. If your MythTV is crashing or you need a backtrace, you need to compile it with this option otherwise the debugging data is useless.
	directv	Installs the DirecTV channel changing script so that you can configure MythTV to use it to change the channels on your DirecTV box.
	dvb	Enables support for Linux DVB cards. These include all cards that work with digital signals such as ATSC, DVB-T, DVB-C, and DVB-S, QAM-64, and QAM-256.
	faad	Uses external faad library for AAC decoding instead of internal libavcodec for decoding AAC. The faad library supports additional AAC types like AAC-LATM that libavcodec does not support
	ieee1394	Allows MythTV to communicate and use Firewire enabled Cable boxes. These are typically found in the United States, where such support is required by law. This will also install Firewire test programs and external channel changers if the internal changer does not work.
	jack	Allows MythTV to use JACK as your sound output device. You will have to manually configure the path to your JACK settings.
	lcd	Tells MythTV that you have an instance of app-misc/lcdproc configured on your machine and it should output information such as current time, show name, episode name, etc to that LCD.
	lirc	Adds LIRC support directly to MythTV allowing for built in control via a LIRC device.
	mmx	Builds ffmpeg's codec libraries with mmx support.
	perl	Builds the perl bindings for MythTV. Allows you to write scripts in Perl to control your MythTV setup or communicate with it.
	tiff	Add support for tiff loading and rendering which is only used by media-plugins/mythgallery
	vdpau	enable support of NVIDIA's VDPAU for video playback
	video_cards_nvidia	When combined with the xvmc USE flag, enables NVIDIA specific XvMC extension usage.
	xvmc	Instructs MythTV to use XvMC for its video output. By default, this will use the generic XvMC wrapper unless a specific video card driver is enabled via their VIDEO_CARDS USE flags.
tvbrowser	themes	Install extra theme packs
tvtime	alsa	Enables an EXPERIMENTAL ALSA patch by the Ubuntu maintainers. Several problems were reported, use with care.
xawtv	xext	Enable use of XFree extensions (DGA,VidMode,DPMS)
xawtv	zvbi	Enable VBI Decoding Library for Zapping
xbmc	airplay	enable AirPlay support
	bluray	Enable playback of Blu-ray filesystems
	goom	Enable GOOM visualization plugin
	midi	Support MIDI files
	projectm	Enable projectM visualization plugin
	pvr	Enable MythTV support
	rsxs	Enable really slick X screensavers
	rtmp	Enable Real Time Messaging Protocol using librtmp
	vaapi	Enables VAAPI (Video Acceleration API) for hardware decoding
	vdpau	enable support for Video Decode and Presentation API for Unix
	webserver	Enable internal webserver
	xrandr	Support X randr extension
xmltv	ar	Argentina tv listing grabber
	be	Belgium and Luxemburg tv listing grabber
	brnet	Brazil cable tv listing grabber
	ch	Switzerland bluewin tv listing grabber
	dk	Denmark tv listing grabber
	dtvla	Latin America digital tv listing grabber
	ee	Estonia tv listing grabber
	es	Spain tv listing grabber
	es_laguiatv	Spain alternative grabber
	es_miguiatv	Spain alternative grabber
	eu_epg	EPG grabber for some European countries.
	fi	Finland tv listing grabber
	fr	France tv listing grabber
	hr	Croatia tv listing grabber
	huro	Hungarian tv listing grabber
	is	Iceland tv listing grabber
	it	Italy tv listing grabber
	jp	Japan tv listing grabber
	na_dd	North America tv listing grabber
	na_dtv	North America Direct TV grabber
	na_icons	option for na_dd to download icons
	nc	Caledonie Island tv listing grabber
	nl	Netherlands tv listing grabber
	nl_wolf	Netherlands alternative tv listing grabber
	no	Norway tv listing grabber
	no_gf	Norway Gfeed tv listing grabber
	pt	Portugal tv listing grabber
	re	Reunion Island (France) tv listing grabber
	se_swedb	Sweden tv listing grabber
	tv_check	enable GUI checking
	tv_combiner	enable grabbers combiner
	tv_pick_cgi	enable CGI support
	uk_bleb	Britain tv listing grabber
	uk_rt	Britain alternative tv listing grabber
	za	South Africa tv listing grabber

media-video

Package	Flag	Description
arista	faac	Use external faac library for AAC encoding
arista	nautilus	Add an entry in the Nautilus context menu to transcode media files for a specified device.
avidemux	aften	Enable A/52 (AC-3) audio encoder support
avidemux	amr	Enable Adaptive Multi-Rate format support through media-libs/opencore-amr
bombono-dvd	gnome	Use GVFS for desktop integration
chaplin	transcode	Enable DVD ripping and transcoding
cheese	introspection	Use dev-libs/gobject-introspection for introspection
clive	clipboard	Support reading from X clipboard
	pager	Support pager!?
	password	Support password controlled sites
devede	psyco	psyco python accelerator
dv2sub	kino	install kino plugin
dvd-slideshow	themes	Install theme pack
dvdauthor	graphicsmagick	Use media-gfx/graphicsmagick instead of media-gfx/imagemagick
dvdrip	fping	Enables fping support for cluster rendering
dvdrip	subtitles	Enables support for subtitle ripping
ffmpeg	3dnowext	Enable manually-optimised routines using the AMD 3DNow!Ex SIMD instruction set, present in modern AMD CPUs. (Check for 3dnowext in /proc/cpuinfo to know whether your CPU supports it).
	aacplus	AAC+ encoding via media-libs/libaacplus.
	amr	Enables Adaptive Multi-Rate Audio support
	ass	Enables media-libs/libass based subtitle renderer.
	avconv	Build and install avconv, an alternative command line tool to ffmpeg from media-video/libav.
	avx	Adds support for Advanced Vector Extensions instructions (Intel Sandy Bridge, AMD Bulldozer and later chips)
	cdio	Enables audio CD grabbing with dev-libs/libcdio.
	celt	Adds Xiph CELT audio decoding support via media-libs/celt
	cpudetection	Enables runtime CPU detection (useful for bindist, compatibility on other CPUs)
	dirac	Enable Dirac video support (an advanced royalty-free video compression format) via the reference library: dirac.
	faac	Use external faac library for AAC encoding
	frei0r	Enable frei0r wrapping in libavfilter
	hardcoded-tables	Use pre-calculated tables rather than calculating them on the fly.
	libv4l	Uses media-libs/libv4l for video4linux instead of direct calls. Adds support for more devices via the userspace library.
	mmxext	Enables mmx2 support
	network	Enables network streaming support
	openssl	Enables dev-libs/openssl support. Adds support for encrypted network protocols (TLS/HTTPS).
	pic	Force shared libraries to be built as PIC (this is slower)
	qt-faststart	Build and install qt-faststart application
	rtmp	Enable Real Time Messaging Protocol using librtmp
	schroedinger	Enable Dirac video support (an advanced royalty-free video compression format) via libschroedinger (high-speed implementation in C of the Dirac codec).
	ssse3	faster floating point optimization for SSSE3 capable chips (Intel Core 2 and later chips)
	vaapi	Enables VAAPI (Video Acceleration API) for hardware decoding
	vdpau	Enables VDPAU decoders (requires nVidia video cards and binary nvidia-drivers to offload CPU processing to video card)
	vis	Adds support for SIMD optimizations for UltraSPARC processors.
	vpx	Enables vp8 codec support using libvpx: Decoding vp8 does not require this to be enabled but libvpx can also be used for decoding; encoding vp8 requires this useflag to be enabled though.
ffmpeg2theora	kate	Adds support for Ogg Kate subtitles via libkate.
gnome-mplayer	dconf	Enable support for gnome-base/dconf
google2srt	html	Install HTML documentation
griffith	csv	Enable proper support for csv import (respectively auto-detection encoding of csv files)
h264enc	ogm	Support for OGM container format
hwdecode-demos	vaapi	Enables VAAPI (Video Acceleration API) for hardware decoding
hwdecode-demos	vdpau	Enables VDPAU decoders (requires nVidia video cards to offload CPU processing to video card
kino	gpac	Enable GPAC support when exporting to 3GPP format
kmplayer	npp	Compile the npp backend that plays xembed style browser plugins.
libav	3dnowext	Enable manually-optimised routines using the AMD 3DNow!Ex SIMD instruction set, present in modern AMD CPUs. (Check for 3dnowext in /proc/cpuinfo to know whether your CPU supports it).
	aac	Use external vo-aacenc library for AAC encoding
	amr	Enable Adaptive Multi-Rate Audio support
	avx	Adds support for Advanced Vector Extensions instructions (Intel Sandy Bridge, AMD Bulldozer and later chips)
	cdio	Enable audio CD grabbing with dev-libs/libcdio.
	cpudetection	Enables runtime CPU detection (useful for bindist, compatibility on other CPUs).
	dirac	Enable Dirac video support (an advanced royalty-free video compression format) via the reference library: dirac.
	faac	Use external faac library for AAC encoding (notice: the resulting binaries are unredistributable).
	frei0r	Enable frei0r wrapping in libavfilter
	gpl	Build all GPL licensed code. Without this flag set the package is build under LGPL license.
	hardcoded-tables	Use pre-calculated tables rather than calculating them on the fly.
	mmxext	Enable mmx2 support.
	network	Enable network streaming support.
	openssl	Prefer dev-libs/openssl over net-libs/gnutls to provide SSL/TLS support (notice: the resulting binaries are unredistributable).
	pic	Force shared libraries to be built as PIC (this is slower).
	pulseaudio	Enable pulseaudio input support.
	qt-faststart	Build and install qt-faststart application.
	rtmp	Enable Real Time Messaging Protocol using librtmp instead the native implementation.
	schroedinger	Enable Dirac video support (an advanced royalty-free video compression format) via libschroedinger (high-speed implementation in C of the Dirac codec).
	ssl	Enable SSL/TLS support using dev-libs/openssl or dev-libs/gnutls.
	ssse3	faster floating point optimization for SSSE3 capable chips (Intel Core 2 and later chips).
	vaapi	Enable VAAPI (Video Acceleration API) for hardware decoding.
	vdpau	Enable VDPAU decoders (requires nVidia video cards to offload CPU processing to video card.
	vis	Adds support for SIMD optimizations for UltraSPARC processors.
	vpx	Enable vp8 encoding support using libvpx.
lives	libvisual	Enable libvisual support
mjpegtools	sdlgfx	Enables y4mhist to display a graphical histogram
mjpg-streamer	input_control	Plugin giving ability to control camera movement (only specific cameras)
	input_file	Plugin that watches given directory and send it's content
	input_testpicture	Plugin for sending compiled in, test pictures
	input_uvc	Plugin that sends video stream from UVC compatible camera
	output_autofocus	Auto focusing plugin
	output_file	Plugin that saves received content under given location
	output_http	Small HTTP server plugin which sends WWW directory content and streams image content
	output_rtsp	Plugin which provides a mechanism to take snapshots with a trigger from a UDP packet
	output_udp	Plugin receiving content over UDP and storing to a directory
	v4l	Uses media-libs/libv4l function mapping for input_uvc plugin
	www	Installs WWW content
motiontrack	multiprocess	Enables multi-process support (SMP/cluster) for motiontrack programs
mplayer	3dnowext	Enable 3dnowext cpu instructions
	amr	Enables Adaptive Multi-Rate format support
	ass	SRT/SSA/ASS (SubRip / SubStation Alpha) subtitle support
	bl	Blinkenlights video output
	bluray	Enable playback of Blu-ray filesystems
	bs2b	Enable Bauer stereophonic-to-binaural headphone filter
	cdio	Use libcdio for CD support (instead of cdparanoia)
	cpudetection	Enables runtime CPU detection (useful for bindist, compatibility on other CPUs)
	custom-cpuopts	Fine-tune custom CPU optimizations (UNSUPPORTED)
	dirac	Enable Dirac video support (an advanced royalty-free video compression format) via the reference library: dirac.
	dvdnav	Use forked libdvdnav, navigate menus in GUIs
	dxr3	Enable DXR3/H+ video output
	enca	Enables support for charset discovery and conversion
	faac	Use external faac library for AAC encoding
	faad	Use external faad library for AAC decoding
	libmpeg2	Build support for mpeg2 over media-libs/libmpeg2 rather than using ffmpeg.
	live	Enables live.com streaming media support
	md5sum	Enables md5sum video output
	mmxext	Enables mmx2 support
	mng	MNG input support
	mpg123	Enable support for mp3 decoding over media-sound/mpg123.
	network	Enables network streaming support
	nut	Enables support for the NUT container format
	osdmenu	Enables support for on-screen display (OSD) menus
	pnm	Add PNM video output option, to create PPM/PGM/PGMYUV images
	pvr	Enable Video4Linux2 MPEG PVR
	radio	Enable V4L2 radio interface and support
	rar	Enable Unique RAR File Library
	real	Adds real audo/video support
	rtc	Enables usage of the linux real time clock. The alternative is software emulation of rtc
	rtmp	Enables RTMPDump Streaming Media support
	schroedinger	Enable Dirac video support (an advanced royalty-free video compression format) via libschroedinger (high-speed implementation in C of the Dirac codec).
	shm	Enable support for shm
	ssse3	faster floating point optimization for SSSE3 capable chips (Intel Core 2 and later chips)
	tga	Enables Targa video output
	toolame	Enable toolame MPEG-2 encoding
	tremor	Enable internal support for Vorbis
	twolame	Enable twolame MPEG-2 encoding
	vdpau	Enables experimental VDPAU support (requires nVidia video cards) to offload MPEG2/MPEG4/VC1/WMV CPU processing to video card
	vidix	Support for vidix video output
	vpx	Enables vp8 codec support using libvpx: Decoding vp8 does not require this to be enabled but libvpx can also be used for decoding; encoding vp8 requires this useflag to be enabled though.
	xanim	Enables support for xanim based codecs
	xvmc	Enables X-Video Motion Compensation support
	zoran	Enables ZR360[56]7/ZR36060 video output
mplayer2	3dnowext	Enable 3dnowext cpu instructions
	ass	SRT/SSA/ASS (SubRip / SubStation Alpha) subtitle support
	bl	Blinkenlights video output
	bluray	Enable playback of Blu-ray filesystems
	bs2b	Enable Bauer stereophonic-to-binaural headphone filter
	cdio	Use libcdio for CD support (instead of cdparanoia)
	cpudetection	Enables runtime CPU detection (useful for bindist, compatibility on other CPUs)
	custom-cpuopts	Fine-tune custom CPU optimizations (UNSUPPORTED)
	dvdnav	Use forked libdvdnav, navigate menus in GUIs
	dxr3	Enable DXR3/H+ video output
	enca	Enables support for charset discovery and conversion
	faad	Use external faad library for AAC decoding
	live	Enables live.com streaming media support
	md5sum	Enables md5sum video output
	mmxext	Enables mmx2 support
	mng	MNG input support
	mp3	Enable support for mp3 decoding over media-sound/mpg123 instead of relying on ffmpeg support.
	network	Enables network streaming support
	nut	Enables support for the NUT container format
	osdmenu	Enables support for on-screen display (OSD) menus
	pnm	Add PNM video output option, to create PPM/PGM/PGMYUV images
	pvr	Enable Video4Linux2 MPEG PVR
	radio	Enable V4L2 radio interface and support
	rar	Enable Unique RAR File Library
	real	Adds real audo/video support
	rtc	Enables usage of the linux real time clock. The alternative is software emulation of rtc
	shm	Enable support for shm
	ssse3	Faster floating point optimization for SSSE3 capable chips (Intel Core 2 and later chips)
	symlink	Copy all binaries and configuration into locations occupied by media-video/mplayer and thus act like drop-in replacement.
	tga	Enables Targa video output
	vdpau	Enables experimental VDPAU support (requires nVidia video cards) to offload MPEG2/MPEG4/VC1/WMV CPU processing to video card
	xanim	Enables support for xanim based codecs
	xvmc	Enables X-Video Motion Compensation support
ogmrip	ogm	Support for OGM container format
ogmrip	srt	Support for SRT subtitle format
rtmpdump	gnutls	Use GnuTLS library instead of the default OpenSSL
rtmpdump	polarssl	Use PolarSSL library instead of the default OpenSSL
smplayer2	download-subs	Enable subtitle downloader (requires QuaZip)
totem	bluetooth	Enable support for user-presence detection via the user's bluetooth handset using net-wireless/bluez
	galago	Allow Totem to set your IM client to "away" when a movie is playing in fullscreen using dev-libs/libgalago
	grilo	Use media-libs/grilo to browse media content from various sources
	introspection	Use dev-libs/gobject-introspection for introspection
	iplayer	Enable BBC player support
	lirc	Enable support for controlling Totem with a remote control using app-misc/lirc
	nautilus	Enable the nautilus extension
	python	Build support for dev-lang/python plugins
	tracker	Enable support for searching media files using the indexer app-misc/tracker
	upnp	Enable DLNA support through media-video/coherence
	vala	Enable bindings for dev-lang/vala
	youtube	Enable youtube plugin
transcode	mjpeg	Enables mjpegtools support
	nuv	NuppelVideo container format demuxing
	pic	disable optimized assembly code that is not PIC friendly
	postproc	Build with ffmpeg libpostproc support
tsmuxer	qt4	Installs tsMuxerGUI (needs Qt4)
undvd	ogm	Support for OGM container format
ushare	dlna	Add DLNA (media-libs/libdlna) support
vdr	analogtv	Add support for the analogtv plugin
	atsc	Support for NorthAmerican Broadcast ( rudimentary )
	cmdreccmdi18n	loads translated commands and reccommands files if existing
	cmdsubmenu	Allows the creation of submenus in the commands menu
	cutterlimit	Limit IO bandwith used for cutting
	cutterqueue	Adds a queue of recordings to be cutted
	cuttime	Adjust starttime of cutted recording by length of cut out parts
	ddepgentry	remove duplicate EPG entries
	deltimeshiftrec	Auto delete timeshift recordings
	dolbyinrec	add a dedicated switch to control recording of dolby digital
	dvbplayer	Use some special mpeg-repacker features. Most usable for old recordings or software output devices.
	dvbsetup	Setup for AC3 transfer, disable primary tuner
	dvdarchive	DMH DVD - Archiv ( used by vdr-burn-0.1.0_* )
	dvdchapjump	Jump on capitels on DMH DVD - Archiv
	dvlfriendlyfnames	filter file names on recording
	dvlrecscriptaddon	enhancement for record-script
	dvlvidprefer	controls video-dir choice on recording
	dxr3	Enable tweaks to improve vdr behaviour on dxr3-cards
	em84xx	Add support for em84xx plugin
	graphtft	support for grapftft plugin up from vdr-graphtft-0.1.7
	hardlinkcutter	Speed up cutting by hardlinking unchanged files
	iptv	Enables channel parameters for vdr-iptv and other input plugins
	jumpplay	Enables automatic jumping over cut marks while watching a recording
	liemikuutio	Formerly known as AIO (all-in-one) patch, adds some nice must haves, plus changes from extensions patch
	lircsettings	Allows to change lirc settings delay, freq and timeout values in OSD
	livebuffer	does timeshifting/background recording all the time, allows to rewind live TV
	lnbshare	Enables support for two or more dvb cards sharing the same cable to the lnb
	mainmenuhooks	Allows to replace main menu entries by some special plugins (like epgsearch, extrecmenu, ...)
	menuorg	Enables support for the menuorg-plugin
	noepg	Adds code to selectively disable epg-reception for specific channels
	osdmaxitems	Support for text2skin
	parentalrating	Support Parental Rating
	pinplugin	Support for pin plugin
	rotor	Enable support for plugin vdr-rotor for dish-positioner.
	settime	set system time per script instead of via syscal
	setup	Enable support for the plugin vdr-setup
	softosd	Soft OSD fading with FF-Cards
	sortrecords	allows to change sort order of recordings
	sourcecaps	Adds the ability to define capabilities of dvb-cards (e.g. card1 can receive Sat @28.2E)
	syncearly	start live display as soon as possible, not waiting for sync of audio and video
	timercmd	Adds submenu for user defined commands in timer menu
	timerinfo	Show with chars +/- if space on HD will suffice for a timer
	ttxtsubs	support for ttxtsubs plugin
	validinput	Signal if it is possible to go left/right in lists with chars < >
	volctrl	allows volume control using left/right keys
	wareagleicon	Replace original icon set in menu
	yaepg	Enables support for the plugin vdr-yaepg
vlc	X	Enables support for, e.g., fullscreen mode via the X Window System. By itself, this flag does not build a graphical interface.
	atmo	Enables support for AtmoLight (homebrew Ambient Lighting Technology)
	audioqueue	Enables AudioQueue audio module for Mac OS X.
	avcodec	Enables libavcodec support for video/audio encoding/decoding. libavcodec is part of FFmpeg.
	avformat	Enables libformat support for reading and writing various media containers. libavformat is part of FFmpeg.
	bluray	Enables libbluray for Blu-ray disc support.
	dc1394	Enables IIDC cameras support.
	dirac	Enable Dirac video support (an advanced royalty-free video compression format) via the reference library: dirac.
	direct2d	Enable Win7/VistaPU Direct2D support.
	directx	Enable Win32 DirectX support.
	dshow	Enables Win32 DirectShow support.
	dxva2	Enables Win32 DxVA2 support.
	egl	Enables EGL video output module.
	fbosd	Enables the framebuffer overlay plugin.
	fluidsynth	Enables Fluidsynth MIDI software synthesis (with external sound fonts).
	gcrypt	Enables cryptography support via libgcrypt.
	gme	Enables support for media-libs/game-music-emu for playing various video game music formats.
	gnome	Adds support for GNOME's filesystem abstraction layer, gnome-base/gnome-vfs. This flag is not GUI-related.
	growl	Enables growl notification support (over UDP for remote access and native on OSX)
	httpd	Enables a web based interface for vlc.
	id3tag	Enables id3tag metadata reader plugin.
	ios-vout	Enables iPhone OS video output.
	kate	Adds support for Ogg Kate subtitles via libkate.
	libass	Enables subtitles support using libass.
	libproxy	Enables support for proxy settings in the HTTP access module.
	libtar	Uses libtar instead of the built-in tar reader for reading custom skins.
	libtiger	Enables Ogg Kate subtitles rendering using libtiger.
	libv4l	Enables Libv4l Video4Linux support.
	libv4l2	Enables Libv4l2 Video4Linux2 support (for conversion from various video formats to standard ones, needed to use v4l2 devices with strange formats).
	linsys	Enables support for Linux Linear Systems Ltd. SDI and HD-SDI input cards.
	live	Enables live555 streaming media support (client support for rtsp).
	macosx	Enables Mac OS X gui support.
	macosx-audio	Enables Mac OS X audio module.
	macosx-dialog-provider	Enables Mac OS X dialog module.
	macosx-eyetv	Enables Mac OS X EyeTV (TNT Tuner) module.
	macosx-qtkit	Enables Mac OS X qtkit module: qtcapture (video) and qtsound (audio) module.
	macosx-quartztext	Enables Mac OS X quartz text module.
	macosx-vout	Enables Mac OS X video output module.
	matroska	Enables matroska support using reference libraries (fallback on other existing matroska support if disabled, i.e., matroska enabled FFmpeg)
	media-library	Build the (sqlite based) media library.
	omxil	Enables OpenMAX Integration Layer codec module.
	optimisememory	Enable optimisation for memory rather than performance.
	postproc	Enables image post-processing via libpostproc (part of FFmpeg).
	projectm	Enables the projectM visualization plugin.
	pvr	Enables PVR cards access module.
	qt4	Builds a x11-libs/qt based frontend. It is now the most up-to-date graphical interface available.
	remoteosd	Enables RemoteOSD plugin (VNC client as video filter).
	rtsp	Enables real audio and RTSP modules.
	run-as-root	Allows vlc to start for root. Don't enable this unless you have a very specific (e.g. embedded) need for it!
	schroedinger	Enable Dirac video support (an advanced royalty-free video compression format) via libschroedinger (high-speed implementation in C of the Dirac codec).
	sdl-image	Enables sdl image video decoder (depends on sdl)
	shine	Enables shine fixed point mp3 encoder.
	shout	Enables libshout output.
	sid	Adds support for playing C64 SID files through media-libs/libsidplay-2.
	skins	Enables support for the skins2 interface.
	stream	Enables sout module for audio/video data streaming/transcoding/etc..
	switcher	Enables MPEG2 video switcher stream output module.
	swscale	Enables image scaling and conversion via libswscale (part of FFmpeg).
	twolame	Enables twolame support (MPEG Audio Layer 2 encoder).
	upnp	Enables support for Intel UPnP stack.
	vaapi	Enables VAAPI (Video Acceleration API) for hardware decoding
	vcdx	Enables VCD with navigation via libvcdinfo (depends on cdio)
	vlm	New videolan (media) manager (vlm), a little manager designed to launch and manage multiple streams from within one instance of VLC.
	waveout	Enable win32 waveOut plugin.
wingdi	Enable Win32 GDI module.
wma-fixed	Enables fixed point WMA decoder.
zvbi	Enables support for teletext subtitles via the zvbi library.
winki	mjpeg	Enables mjpegtools support
x264-encoder	10bit	Set output bit depth to 10
	ffmpegsource	Enable ffmpegsource aka ffms support, disables lavf
	interlaced	Enable interlaced encoding support, this can decrease encoding speed by up to 2%
xine-ui	vdr	Enables Video Disk Recorder support

net-analyzer

Package	Flag	Description
aimsniff	http	Install the WAS (Web AIM Sniff) frontend
barnyard	sguil	Enable sguil (The Analyst Console for Network Security Monitoring) support
barnyard2	aruba	Enable Aruba support
	gre	Enable GRE support
	mpls	Enable support for mpls networks
bmon	rrdtool	Enables net-analyzer/rrdtool support
bwm-ng	csv	Enable csv output
bwm-ng	html	Enable html output
cacti	doc	install html documentation
echoping	http	enable support for http protocol.
	icp	enable support for ICP (used to monitor proxies).
	priority	enable socket priority support.
	smtp	enable support for SMTP protocol.
	tos	enable support for TOS (TYpe Of Service).
fprobe	messages	enable console messages
hydra	ncp	NCP protocol (NetWare) support through net-fs/ncpfs
icinga	idoutils	Adds DB support
	lighttpd	Adds Lighttpd support
	plugins	Adds support for nagios plugins
	web	Adds generic web interface support
lilac	nmap	Installs nmap which can be used to automatically discover devices to monitor.
linkchecker	bookmarks	Mozilla Bookmark parsing
	login	login form submission
	syntax-check	HTML/CSS syntax checks
metasploit	gui	Enable Java GUI
munin	asterisk	installs deps for monitoring Asterisk
	irc	installs deps for monitoring IRC
	memcached	installs deps for monitoring memcached
	minimal	installs only the munin-node, applicable if the host is not the munin master installation"
nagios-core	lighttpd	install www-servers/lighttpd config
nagios-core	web	enable web interface
nagios-nrpe	command-args	allow clients to specify command arguments
nagios-plugins	nagios-dns	installs deps for dns monitoring
	nagios-game	installs deps for monitoring games-util/qstat
	nagios-ntp	installs deps for ntp monitoring
	nagios-ping	installs deps for fancy ping monitoring
	nagios-ssh	installs deps for monitoring ssh
	ups	installs deps for monitoring Network-UPS (sys-power/nut)
nagvis	automap	Enable automated map generation using media-gfx/graphviz
ncrack	ssh	Compile and link against the internal openssh modified library.
net-snmp	diskio	Enable the use of diskio mibs
	elf	Enable the use of elf utils to check uptime on some systems
	extensible	build deprecated extensible mib module (extend is successor)
	mfd-rewrites	Use MFD rewrites of mib modules where available
	rpm	Enable the rpm snmp probing
	sendmail	Enable sendmail statistics monitoring
	smux	Enable the smux MIBS module
nfdump	compat15	Enable read support for nfdump data files created with nfdump 1.5.x
	ftconv	Build the flow-tools to nfdump converter
	nfprofile	Build nfprofile used by NfSen
	sflow	Build sflow collector sfcpad
pchar	pcap	Use the net-libs/libpcap library
pmacct	64bit	Use 64bit counters instead of 32bit ones
pmacct	ulog	Enable ULOG support
rrdcollect	exec	Enable exec:/// support
rrdcollect	librrd	Use the librrd library from net-analyzer/rrdtool
rrdtool	rrdcgi	Build rrdcgi support
sancp	sguil	Enable sguil (The Analyst Console for Network Security Monitoring) support
scanlogd	nids	Use net-libs/libnids for packet capturing
scanlogd	pcap	Use net-libs/libpcap for packet capturing
scapy	pyx	Enable dev-python/pyx support for psdump/pdfdump commands
	tcpreplay	Enable net-analyzer/tcpreply support for fast packet replay
	visual	Enable dev-python/visual support for 3d graphs
smokeping	speedy	Use dev-perl/SpeedyCGI instead of perl to speed up cgi scripts
snort	active-response	Enables support for automatically sending TCP resets and ICMP unreachable messages to terminate connections. Used with inline deployments.
	aruba	Adds support for monitoring wireless traffic using a Aruba Mobility Controler.
	decoder-preprocessor-rules	Added support to provide action control (alert, drop, pass, etc) over preprocessor and decoder generated events.
	dynamicplugin	Enable ability to dynamically load preprocessors, detection engine, and rules library. This is required if you want to use shared object (SO) snort rules.
	flexresp	(DEPRECIATED) Original method for enabling connection tearing for inline deployments. Replaced with flexresp3 in Snort-2.9.0.
	flexresp2	(DEPRECIATED) Replaced flexresp for enabling connection tearing for inline deployments. Replaced with flexresp3 in Snort-2.9.0.
	flexresp3	Enables support for new flexable response preprocessor for enabling connection tearing for inline deployments. Replaces flexresp and flexresp2.
	gre	Enable support for inspecting and processing Generic Routing Encapsulation (GRE) packet headders. Only needed if you are monitoring GRE tunnels.
	inline	(DEPRECIATED) Enables support for deploying snort inline. Uses net-firewall/iptables, via libipq, rather than net-libs/libpcap. Replaced by DAQ in Snort-2.9.0
	inline-init-failopen	Enables support to allow traffic to pass (fail-open) through inline deployments while snort is starting and not ready to begin inspecting traffic. If this option is not enabled, network traffic will not pass (fail-closed) until snort has fully started and is ready to perform packet inspection.
	large-pcap-64bit	Allows Snort to read pcap files that are larger than 2 GB. ONLY VALID FOR 64bit SYSTEMS!
	linux-smp-stats	Enable accurate statistics reporting through /proc on systems with multipule processors.
	mpls	Enables support for processing and inspecting Multiprotocol Label Switching MPLS network network traffic. Only needed if you are monitoring an MPLS network.
	normalizer	Enables support for normalizing packets in inline deployments to help minimize the chances of detection evasion.
	paf	Enables support for Protocol Aware Flushing. This allows Snort to statefully scan a stream and reassemble a complete protocol data unit regardless of segmentation.
	perfprofiling	Enables support for preprocessor and rule performance profiling using the perfmonitor preprocessor.
	ppm	Enables support for setting per rule or per packet latency limits. Helps protect against introducing network latency with inline deployments.
	react	Enables support for the react rule keyword. Supports interception, termination, and redirection of HTTP connections.
	reload	Enables support for reloading a configuration without restarting snort.
	reload-error-restart	Enables support for completely restarting snort if an error is detected durring a reload.
	targetbased	Enables support in snort for using a host attibute XML file (attribute_table.dtd). This file needs to be created by the user and should define the IP address, operating system, and services for all hosts on the monitored network. This is cumbersome, but can improve intrusion detection accuracy.
	timestats	(DEPRECIATED) Enables support for printing packet stats on a per hour and per protocol breakdown. Depreciated in Snort-2.9.0.
	zlib	Enables HTTP inspection of compressed web traffic. Requires dynamicplugin be enabled.
symon	perl	Enables a generic perl symux client
	symon	Enables the system monitor. Offers no functionality but monitoring and forwarding of measured data
	symux	Enables the multiplexer which stores incoming symon streams on disk in RRD (net-analyzer/rrdtool) files
tcpdump	chroot	Enable chrooting when dropping privileges
tcpdump	smi	Build with net-libs/libsmi to load MIBs on the fly to decode SNMP packets
tcpreplay	pcapnav	Enable if you want the jump to byte offset feature via net-libs/libpcapnav
tcpreplay	tcpdump	Use net-analyzer/tcpdump for packet decoding feature
wireshark	ares	Use GNU net-dns/c-ares library to resolve DNS names
	doc-pdf	Build documentation in pdf format (US and a4 paper sizes)
	gcrypt	Use GNU crypto library (dev-libs/libgcrypt) to decrypt ipsec traffic
	pcap	Use net-libs/libpcap for network packet capturing (build dumpcap, rawshark)
	smi	Use net-libs/libsmi to resolve numeric OIDs into human readable format
zabbix	agent	Enable zabbix agent (for to-be-monitored machines)
	frontend	Enable zabbix web frontend
	openipmi	Enable openipmi things
	proxy	Enable proxy support
	server	Enable zabbix server
	ssh	Enable ssh.run items

net-dialup

Package	Flag	Description
capi4k-utils	fax	Install capi-fax demo programs
	pppd	Installs pppdcapiplugin modules
	rcapid	Installs rcapid daemon
freeradius	edirectory	Enables Novell eDirectory integration
	frascend	Enables Ascend binary mode
	frxp	Enables experimental modules
	udpfromto	Compile in UDPFROMTO support (enables freeradius to specify source address correctly in multi-homed setups)
freeradius-client	scp	Add service type hints derived from username prefix
freeradius-client	shadow	Enable shadow password support
mgetty	fax	Enables fax support
mgetty	fidonet	Enables FidoNet support
misdn	ecaggressive	Make the selected echo canceller a little more aggressive
	eckb1	Use the KB1 echo canceller
	ecmark2	Use the MARK2 echo canceller
	ecmg2	Use the MG2 echo canceller (default)
ppp	activefilter	Enables active filter support
	atm	Enables ATM (Asynchronous Transfer Mode) protocol support
	dhcp	Installs PPP DHCP client plugin for IP address allocation by a DHCP server (see http://www.netservers.co.uk/gpl/)
	eap-tls	Enables support for Extensible Authentication Protocol and Transport Level Security (see http://www.nikhef.nl/~janjust/ppp/index.html)
	gtk	Installs GTK+ password prompting program that can be used by passprompt.so PPP plugin for reading the password from a X11 input terminal
	ipv6	Enables support for IP version 6
	mppe-mppc	Enables support for MPPC (Microsoft Point-to-Point Compression) - NEEDS A PATCHED KERNEL <=2.6.14 (see http://mppe-mppc.alphacron.de)
	pam	Enables PAM (Pluggable Authentication Modules) support
	radius	Enables RADIUS support
pptpd	gre-extreme-debug	Log all GRE accepted packages when in debug mode (required if you want upstream support)
xl2tpd	dnsretry	Patch for host lookup retries, activated by redial feature

net-dns

Package	Flag	Description
avahi	autoipd	Build and install the IPv4LL (RFC3927) network address configuration daemon
	bookmarks	Install the avahi-bookmarks application (requires dev-python/twisted)
	gtk3	Build the avahi-ui-gtk3 library, and use gtk3 for the avahi utilities under USE=utils
	howl-compat	Enable compat libraries for howl
	introspection	Use dev-libs/gobject-introspection for introspection
	mdnsresponder-compat	Enable compat libraries for mDNSResponder
	utils	Install the avahi gtk+ utils avahi-discover, bssh, and bvnc
bind	dlz	Enables dynamic loaded zones, 3rd party extension
	gost	Enables gost OpenSSL engine support
	gssapi	Enable gssapi support
	pkcs11	Enable PKCS#11 key support/tools for DNSSEC
	resolvconf	Enable support for net-dns/openresolv
	rpz	Enable response policy rewriting (rpz)
	sdb-ldap	Enables ldap-sdb backend
	urandom	Use /dev/urandom instead of /dev/random
bind-tools	gssapi	Enable gssapi support
	pkcs11	Enable PKCS#11 key support/tools for DNSSEC
	urandom	Use /dev/urandom instead of /dev/random
ddclient	hardened	Use iproute2 instead of ifconfig to grab an IP address
ddclient	ssl	Connect to the server utilizing SSL
dnsmasq	conntrack	Add support for Linux conntrack connection marking.
	dhcp	Enable support for reading ISC DHCPd lease files
	tftp	Enables built in TFTP server for netbooting
ldns-utils	gost	Enable GOST support
maradns	authonly	Allows one to build only authoritative DNS server
mydns	alias	Enable David Phillips aliasing
mydns	status	Enable the STATUS opcode to check server status
opendnssec	auditor	Enables auditing capabilities for OpenDNSSEC
	eppclient	Enables support for automatic submission of DNSSEC keys to an upstream epp server
	external-hsm	Enables support for storing DNSSEC keys through an arbitrary non-portage PKCS#11 interface, specified through an environment variable
	opensc	Enables support for storing DNSSEC keys through a dev-libs/opensc PKCS#11 interface
	signer	Enables signing capabilities for OpenDNSSEC
	softhsm	Enables support for storing DNSSEC keys in a dev-libs/softhsm PKCS#11 object
pdns	opendbx	Enable the OpenDBX backend
pdnsd	isdn	Linux-only: check status of ippp interfaces with ISDN-specific system calls.
pdnsd	urandom	Linux-only: use /dev/urandom (pseudo-random number generation) instead of the default use of random() PRNG.
resolvconf-symlink	symlink	Actually replace /etc/resolv.conf with a symlink. Without this flag, the ebuild is a no-op.
unbound	gost	Enable GOST support

net-firewall

Package	Flag	Description
arno-iptables-firewall	plugins	Install optional plugins
ipsec-tools	hybrid	Makes available both mode-cfg and xauth support
	idea	Enable support for the IDEA algorithm
	nat	Enable NAT-Traversal
	rc5	Enable support for the patented RC5 algorithm
iptables	netlink	Build against libnfnetlink which enables the nfnl_osf util
nufw	nfconntrack	Use netfilter_conntrack
	nfqueue	Use NFQUEUE instead of QUEUE
	pam_nuauth	Add support for pam nufw from PAM
	plaintext	Add support for authentication with plaintext files

net-fs

Package	Flag	Description
autofs	hesiod	Install hesiod module
	ldap	Install LDAP module
	sasl	Enable SASL support in the LDAP module
cifs-utils	ads	Enable Active Directory support
	caps	libcap support
	caps-ng	libcap-ng support
	creds	cifs credentials support
	upcall	Create cifs.idmap binary; idmap support
coda	client	Build and install the client components of coda filesystem. At least one of client or server should be enabled.
	coda_layout	Use legacy filesystem layout instead of FHS compliant one. Note: /coda symlink is installed unconditionally when FHS layout is used. Therefore the /coda namespace is preserved with either layout.
	coda_symlinks	Install legacy symlinks when FHS layout has been selected (-coda_layout). You should only need this if you use local scripts or 3rd party apps relying on precise layout. Note: /coda symlink is installed unconditionally, so the namespace is preserved in any case.
	server	Build and install the server components of coda filesystem. Note: at least one of client/server flags must be enabled.
netatalk	appletalk	Build support for Apple's AppleTalk (DDP) protocol and its utilities (atalkd, timelord, papd).
	cups	Add support for net-print/cups printers in papd. This flag is only considered if appletalk USE flag is enabled, and is otherwise ignored.
	quota	Add support for user quota on various filesystems.
	ssl	Use dev-libs/openssl to provide DHX User Access Modules. These are not used with most recent versions of OS X and can be kept disabled without risks.
	xfs	Enable support for XFS Quota
nfs-utils	nfsidmap	Enable support for newer nfsidmap helper
	nfsv3	Enable support for NFSv3
	nfsv4	Enable support for NFSv4
	nfsv41	Enable support for NFSv4.1
	nonfsv4	Disable support for NFSv4
samba	addns	Enable AD DNS integration
	ads	Enable Active Directory support
	aio	Enable asynchronous IO support
	client	Enables the client part
	cluster	Enable support for clustering
	dso	Enable dso support
	fulltest	Enabling extra tests in test phase
	iprint	Enabling iPrint technology by Novell
	krb5	Enable kerberos support
	ldb	Enable the ldb tools
	netapi	Enable building of netapi bits
	quota	Enables support for user quotas
	server	Enables the server part
	smbclient	Enable smbclient tool
	smbsharemodes	Enable special smb share modes (?)
	smbtav2	Enable Samba Traffic Analyzer version 2
	swat	Enables support for swat configuration gui
	tools	Enable extra tools
	winbind	Enables support for the winbind auth daemon
smbnetfs	gnome	Use the gnome-base/gnome-keyring for password management.

net-ftp

Package	Flag	Description
proftpd	authfile	Enable support for the auth-file module
	ban	Enable support for the mod_ban module
	case	Enable support for the mod_case module
	copy	Enable support for the mod_copy module
	ctrls	Enable support for the mod_ctrls and mod_ctrls_admin modules
	deflate	Enable support for the mod_deflate module
	diskuse	Enable support for the mod_diskuse module
	exec	Enable support for the mod_exec module. WARNING: this could be a security risk
	ident	Enable support for the mod_ident module
	ifsession	Enable support for the ifsession module
	ifversion	Enable support for the mod_ifversion module
	memcache	Enable support for the mod_memcache module, for using memcached servers
	qos	Enable support for the mod_qos module
	ratio	Enable support for the mod_ratio module
	readme	Enable support for the mod_readme module
	rewrite	Enable support for the rewrite module
	sftp	Enable support for the mod_sftp module and optionally mod_sftp_sql and mod_sftp_pam if matching USE flags are enabled
	shaper	Enable support for the mod_shaper module
	sitemisc	Enable support for the sitemisc module
	softquota	Enable support for the quotatab module
	trace	Build with trace support. Should not be enabled on production servers
	vroot	Enable support for the virtual root module
pure-ftpd	anondel	Permit anonymous to delete files
	anonperm	Permit anonymous to change file permissions
	anonren	Permit anonymous to rename files
	anonres	Permit anonymous to resume file transfers
	charconv	Enables charset conversion
	noiplog	Disables logging of IP addresses
	paranoidmsg	Display paranoid messages instead of normal ones
	resolveids	Resolve UIDs/GIDs
	sysquota	Enables system quota support (needs sys-fs/quota)
	vchroot	Enable support for virtual chroot (possible security risk)
twoftpd	breakrfc	Break RFC compliance to allow control symbols in filenames (required for some (e.g. cp1251) encodings, use with caution).

net-im

Package	Flag	Description
ayttm	irc	Enable Internet Relay Chat support
	lj	Enable livejournal.com support
	smtp	Adds support for sending messages via RFC2821 SMTP
	webcam	Adds webcam support for Yahoo Messenger
bitlbee	libevent	Use libevent for event handling
	nss	Use NSS for SSL support in MSN and Jabber
	otr	Enable support for encrypted conversations
	plugins	Enable support for plugins
	purple	Use libpurple instead of the built-in IM protocol support
	twitter	Enable Twitter protocol support
centerim	gadu	Enable support for the Gadu-Gadu protocol
	irc	Enable support for the IRC protocol
	lj	Enable support for the LiveJournal weblog system
	otr	Enable encrypted conversations
choqok	ayatana	Build in support for Ayatana notification using the libindicate-qt plugin.
climm	otr	Enable encrypted conversations
ejabberd	captcha	Support for CAPTCHA Forms (XEP-158)
	mod_irc	Build irc gateway
	mod_muc	Build Multi User Chat module
	mod_proxy65	Support for SOCKS5 Bytestreams (XEP-0065)
	mod_pubsub	Build Pubsub module
	mod_statsdx	Measures several statistics, and provides a new section in ejabberd Web Admin to view them.
	web	Enable web admin interface
ekg2	gadu	Enable Gadu-Gadu protocol support (requires net-libs/libgadu).
	gif	GIF token support for Gadu-Gadu protocol.
	gnutls	Enable SSL/TLS support through GnuTLS for the plugins supporting it. If 'ssl' is enabled too, GnuTLS will be preferred where possible (and OpenSSL will be used elsewhere).
	gpg	Enable jabber message encryption through app-crypt/gpgme.
	inotify	Enable inotify-based filesystem moniotoring support for xmsg&mail plugins.
	jpeg	JPEG token support for Gadu-Gadu protocol.
	oracle	Support logging messages into Oracle database.
	sqlite	Support logging messages into SQLite2 database. If 'sqlite3' is set too, it will be used instead.
	sqlite3	Support logging messages into SQLite3 database. If 'sqlite' is set too, SQLite3 will be used.
	ssl	Enable the complete SSL/TLS support through OpenSSL. This also enables the 'sim' plugin which relies on OpenSSL.
emesene	webcam	Enable support for webcam
empathy	call	Enable Call channel support using net-libs/telepathy-farstream for audio/video calls
	geoloc	Enable geolocation support through app-misc/geoclue
	gnome-online-accounts	Enable using net-libs/gnome-online-accounts for authorization (e.g. for Google Talk)
	map	Enable world map support through media-libs/libchamplain
	nautilus	Enable nautilus-sendto support
	sendto	Enable support for sending files to various devices using gnome-extra/nautilus-sendto
	webkit	Build support for Adium-style HTML-based conversation window themes using net-libs/webkit-gtk
gajim	gmail	Depend on net-dns/bind-tools to get gmail chats working
	idle	Enable idle module
	srv	SRV capabilities
	xhtml	Enable XHTML support
gnugadu	tlen	Enable Tlen.pl protocol support
jabberd2	memdebug	Enable nad and pool debug. Requires USE="debug" to be set.
kadu	gadu	Enables Gadu communication protocol
	mpd	Enables Music Player Daemon support
	phonon	Enables phonon audio plugin
	sdk	Install Kadu SDK (cmake module, API headers)
	speech	Enables speech module
kmess	konqueror	Enable integration with konqueror
kmess	libnotify	Enable desktop notifications using the knotify library
leechcraft-azoth	acetamide	Build Acetamide, the IRC protocol support
	adiumstyles	Build support for Adium styles
	astrality	Build Astrality, support for protocols provided by Telepathy
	autoidler	Build support for automatic status changing according to user idle time
	autopaste	Build Autopaste for pasting long texts to pastebins
	chathistory	Build ChatHistory which stories chat history
	depester	Build Depester which enables to ignore MUC participants
	embedmedia	Build EmbedMedia for embedding flash videos and images directly into chat windows
	herbicide	Build Herbicide, a basic antispam plugin
	hili	Build HiLi which allows to customize highlight settings in MUCs
	isterique	Build Isterique plugin for neutralizing excessive caps lock usage
	juick	Build plugin for the Juick.com microblogging service
	lastseen	Build plugin for client-side recording of the last online/available time
	metacontacts	Build plugin for metacontacts support
	modnok	Build Modnok for in-chat LaTeX formulae rendering
	nativeemoticons	Build support for native Azoth's emoticons packs
	otroid	Build OTRoid, plugin for the Off-the-Record deniable encryption system
	p100q	Build p100q, plugin for psto.net microblogging service
	rosenthal	Build Rosenthal, the spellchecker plugin
	standardstyles	Build support for standard Azoth styles engine
	xoox	Build Xoox, gloox-based plugin for XMPP support
	xtazy	Build Xtazy for publishing currently playing tune
	zheet	uild Zheet, libmsn-based plugin for Windows Live Messenger support
mcabber	aspell	Adds support for app-text/aspell spell checker.
mcabber	otr	Enable encrypted conversations using Off-The-Records messaging
minbif	video	Add video support
pidgin	gadu	Enable Gadu Gadu protocol support
	groupwise	Enable Novell Groupwise protocol support
	gstreamer	Enables voice and video sessions
	gtk	Builds Pidgin, the GTK+ interface
	meanwhile	Enable meanwhile support for Sametime protocol
	ncurses	Build finch, console interface
	prediction	Enable Contact Availability Prediction plugin
	python	Build libgnt (GLib Ncurses Toolkit used by finch) with python scripting support
	silc	Enable SILC protocol support
	xscreensaver	Use X screensaver protocol extension to monitor idle/active status based on mouse/keyboard events
	zephyr	Enable Zephyr protocol support
prosody	libevent	Use libevent for event handling
	sql	Require dev-lua/luadbi for SQL storage plugins
	zlib	Support for compressing XMPP streams with mod_compression
psi	enchant	Use enchant spell engine instead of aspell
	extras	Enables extra non official patches
	iconsets	Install additional iconsets, some of them has not clear licensing
	plugins	Enable plugins support
	powersave	Disable some non critical timers for much less CPU usage
	webkit	Enable chatlog rendering using webkit
	whiteboarding	Enable experimental interactive SVG drawing
	xscreensaver	Use X screensaver protocol extension to monitor idle/active status based on mouse/keyboard events
psimedia	demo	build simple test application for the PsiMedia system
pyaim-t	webinterface	Install dependencies needed for the web interface
pyicq-t	webinterface	Install dependencies needed for the web interface
qutim	histman	Enable histman plugin
	irc	Enable irc support
	mrim	Enable mrim plugin
	vkontakte	Enable vkontakte plugin
	yandexnarod	Enable yanderx.narod plugin
skype	qt-static	Installs binaries statically linked to Qt
telepathy-connection-managers	irc	Enable Internet Relay Chat (IRC) support.
	jabber	Enable XMPP protocol handler (this is also Google Talk).
	sip	Enable SIP/SIMPLE messaging and calling.
	yahoo	Enable Yahoo! messaging support.
	zeroconf	Enable Link-Local Messaging via the zeroconf or Bonjour protocol.
telepathy-logger	introspection	Use dev-libs/gobject-introspection for introspection
telepathy-mission-control	upower	Use sys-power/upower to detect suspend and resume
tkabber	extras	Enables extra non official patches
tkabber	plugins	Enables installation the extra plugins
vacuum	adiummessagestyle	Use UI styles created for Adium
	annotations	Enable adding comments to the contacts in the roster
	autostatus	Change the status in accordance with the time of inactivity
	avatars	Enable assigning and displaying avatars
	birthdayreminder	Reminds about birthdays of your friends
	bitsofbinary	Allow other modules to receive or send a small amount of binary data in XMPP stanza
	bookmarks	Enable creating bookmarks of the Jabber conferences and Web pages
	captchaforms	Perform tests for humanity outside of Web browser
	chatstates	Post user's activity to the chat
	clientinfo	Enable sending and receiving peer's application version, local time and last activity info
	commands	Enable performing special commands provided by various services
	compress	Compress stream of messages
	console	Enable inspecting a raw XML stream
	dataforms	Allow other modules to process and display data forms intended for the user
	datastreamsmanager	Enable initiating a custom data stream between two XMPP entities
	emoticons	Enable using smiley images in messages
	filestreamsmanager	Enable transferring files between two XMPP entities
	filetransfer	Enable sending files to peers
	gateways	Simplify the interaction with gateways to other IM systems
	inbandstreams	Enable initiating in-band data stream between two XMPP enitites
	iqauth	Enable logging on Jabber servers withous SASL authentication support
	jabbersearch	Enable searching contacts in Jabber networks
	messagearchiver	Enable saving the communication history both locally and on the server
	multiuserchat	Enable Jabber multi-user conferences
	pepmanager	Allows other plugins to recieve and publish PEP events
	privacylists	Enable blocking the undesirable contacts
	privatestorage	Allow other modules to store arbitrary data on the server
	registration	Enable creating accounts in Jabber services
	remotecontrol	Allows to remotely control the client
	rostersearch	Allows to search for contacts in the roster
	servicediscovery	Enable receiving information about Jabber entities
	sessionnegotiation	Enable initiating the session between two entities with setting the rules for XMPP stanzas exchange
	socksstreams	Enable initiating SOCKS5 data streams between two XMPP entities
	vcard	Enable obtaining peer's personal contact information
	vcs-revision	Add VCS revision to version number, INSECURE.
	xmppuriqueries	Allow other plugins to handle XMPP URI queries

net-irc

Package	Flag	Description
atheme-services	cracklib	Enable nickserv/cracklib module for enforcing strong account passwords
	largenet	Enable support/tweaks for large networks
	ldap	Enable ldap-backed authentication module
	perl	Install a perl module which wraps around the services' XML-RPC interface
bip	freenode	Enables freenode-specific functionality. Currently that is only support for mute lists (MODE #channel +q).
	noctcp	Disable the automatic CTCP VERSION reply which is often exploited by malicious people to cause a DoS (reconnect due to flooding).
	oidentd	Enable oidentd support
epic5	archive	Use app-arch/libarchive to use zip and tar archives from scripts.
epic5	valgrind	Compile against dev-util/valgrind headers to improve memory-leak checking when running epic5 under valgrind.
ezbounce	boost	Compile against dev-libs/boost libraries
inspircd	openssl	Build dev-libs/openssl module
kvirc	dcc_video	Support video connections over DCC protocol
	dcc_voice	Support voice connections over DCC protocol
	ipc	Support inter-process communication between KVIrc processes
	phonon	Support Phonon for audio output
	qt-dbus	Support Qt-DBus
	qt-webkit	Support Qt-WebKit
	transparency	Support pseudo-transparency
ngircd	ident	Enables support for net-libs/libident
psybnc	multinetwork	Adds support for multiple networks
	oidentd	Adds support for oidentd
	scripting	Adds scripting support
quassel	X	Build the Qt 4 GUI client for quassel. If this USE flag is disabled, the GUI is not built, and cannot be used. You might want to disable this on the server, but you need it enabled on the client.
	ayatana	Build in support for Ayatana notification using the libindicate-qt plugin.
	crypt	Support core->network per-channel and per-query blowfish encryption via app-crypt/qca:2.
	monolithic	Build Standalone client with integrated core, no external quasselcore needed. Only useful if you don't want to use quassels client/server model. The server and X flags are not needed in this case but it is possible to enable them too.
	phonon	Build client with phonon backend support. This enables sound playback in client.
	server	Build the server binary. If this USE flag is disabled, the 'core' server binary for quassel is not built, and cannot be used. You need this enabled on the server, but you might want to disable it on the client.
	webkit	Use qt-webkit rendering engine for showing URL thumbnails and for other things that need web browser integration.
rbot	aspell	Use aspell instead of ispell in the "spell" plugin for rbot. The vanilla plugin uses ispell, but enabling this flag makes it use the ispell interface from aspell instead.
	cal	Add dependency over a package providing the /usr/bin/cal command, which is needed to enable the "cal" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
	dict	Add dependency over dev-ruby/ruby-dict, which is needed to enable the "dict" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
	figlet	Add dependency over app-misc/figlet, which is used by the "figlet" plugin for rbot. If the USE flag is disabled the plugin will be unable to use figlet; if toilet is also disabled, the plugin will be disabled.
	fortune	Add dependency over games-misc/fortune-mod, which is needed to enable the "fortune" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
	host	Add dependency over net-dns/bind-tools (providing /usr/bin/host), which is needed to enable the "host" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
	hunspell	Use hunspell instead of ispell in the "spell" plugin for rbot. The vanilla plugin uses ispell, but enabling this flag makes it use the ispell interface from hunspell instead. It's overridden by the aspell USE flag. For native hunspell support check the rbot-hunspell plugin.
	nls	Build and install translation for the messages coming from the bot and its plugins (through dev-ruby/ruby-gettext).
	shorturl	Add dependency over dev-ruby/shorturl, which is needed to enable the "shortenurl" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
	timezone	Add dependency over dev-ruby/tzinfo to enable the "time" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
	toilet	Add dependency over app-misc/toilet, which is used by the "figlet" plugin for rbot. If the USE flag is disabled the plugin will be unable to use toilet; if figlet is also disabled, the plugin will be disabled.
	translator	Add dependency over dev-ruby/mechanize, which is needed to enable the "translator" plugin for rbot. If the USE flag is disabled the plugin is also disabled by default.
srvx	bahamut	Choose bahamut protocol over p10 protocol
supybot	twisted	Allows supybot to use dev-python/twisted as driver
unrealircd	extban-stacking	Enable extended channel bans (such as +b ~c: and +b ~n:) to contain other extended bans instead of just hostmasks.
	hub	Enable hub support
	operoverride	Enable OperOverride extension
	operoverride-verify	Enable requiring opers to invite themselves to +s/+p channels
	prefixaq	Enable chanadmin and chanowner prefixes
	showlistmodes	Support displaying channel modes in /list
	shunnotices	Enable notifying a user when un-shunned
	spoof	Enable the spoof protection
	topicisnuhost	Enable displaying nick!user@host as topic setter
	usermod	Enable /set* and /chg* commands
weechat	alias	Enable plugin for alias control.
	charset	Enable encoding conversions.
	fifo	Enable FIFO support (sh pipes).
	irc	Enable IRC protocol support.
	logger	Enable support for logging.
	relay	Enable relay plugin (experimental)
	rmodifier	Enable rmodifier plugin.
	scripts	Build infrastructure for scripting.
	xfer	Enable xfer plugin support.
xchat	fastscroll	Make scrolling of large text buffers faster by circumventing some of pango's overhead
	hires-icons	Install custom high-resolution icons instead of the default one
	ntlm	Enable NTLM authentication
	xchatdccserver	Enables support for the /dccserver command via a patch
	xchatnogtk	Disables building the GTK front end to XChat
xchat-xsys	audacious	Enables media-sound/audacious integration
znc	ares	Enables support for asynchronous DNS using the c-ares library
	dns-threads	Use threads for DNS resolving
	extras	Enable some additional modules

net-libs

Package	Flag	Description
aqbanking	chipcard	Enable support for DDV/RSA-chipcards
c-client	doc	Install RFCs related to IMAP
courier-authlib	vpopmail	Enable vpopmail support
cvm	vpopmail	Enable vpopmail support
daq	afpacket	Build the AFPacket data acquisition module. Functions similar to the PCAP module but with better performance. Snort can run unprivileged when using this module. AFpacket supports both inline and passive modes.
	dump	Build the Dump data acquisition module. The dump DAQ allows you to test the various inline mode features available in 2.9 Snort like injection and normalization.
	ipq	Build the IPQ data acquisition module. IPQ is the old way to process iptables packets for inline deployments. Snort can not run unprivileged when using this module.
	nfq	Build the NFQ data acquisition module. NFQ is the new way to process iptables packets for inline deployments. Snort can not run unprivileged when using this module.
	pcap	Build the PCAP data acquisition module.
farsight2	upnp	Enable UPnP IGD support
glib-networking	gnome	Extract HTTP/HTTPS/SOCKS proxy configuration stored using GSettings
glib-networking	libproxy	Use net-libs/libproxy for getting the HTTP/HTTPS/SOCKS proxy configuration
gnome-online-accounts	introspection	Use dev-libs/gobject-introspection for introspection
gnutls	nettle	Use dev-libs/nettle as crypto backend
gnutls	pkcs11	Add support for PKCS#11 over app-crypt/p11-kit
gssdp	introspection	Use dev-libs/gobject-introspection for introspection
gtk-vnc	gtk3	Build the gtk3 gtk-vnc library and other gtk3 assets
	introspection	Use dev-libs/gobject-introspection for introspection
	vala	Enable bindings for dev-lang/vala
gupnp	introspection	Use dev-libs/gobject-introspection for introspection
gupnp-av	introspection	Use dev-libs/gobject-introspection for introspection
gupnp-igd	introspection	Use dev-libs/gobject-introspection for introspection
iax	snomhack	Use slower memset for SNOM phoneem
ldns	gost	Enable GOST support
libeXosip	srv	enable support for SRV records DNS queries
libesmtp	ssl	Enable support for advanced SMTP authentication methods, like NTML and STARTTLS. Also use OpenSSL's MD5 implementation over internal version.
libetpan	liblockfile	Enable support for liblockfile library
libgsasl	gcrypt	Use dev-libs/libgcrypt for low-level crypto
libinfinity	server	Build and install the server binary including init.d/conf.d-scripts. Needed if you want to host an infinote server for gobby.
libmicrohttpd	messages	enable error messages
libnice	upnp	Enable UPnP IGD support
libnids	glib	Use dev-libs/glib for multiprocessing support
libnids	libnet	Include code requiring net-libs/libnet
liboauth	bindist	Alias for the nss USE flag, since there are license compliancy trouble when using OpenSSL.
	curl	If enabled, net-misc/curl is used thorugh the libcurl library; if it's not, the curl command is used instead. Some features are only available when using the library, but using it as library requires matching SSL implementations.
	nss	Use Mozilla NSS (dev-libs/nss) as hash library; if this is disabled, dev-libs/openssl is used instead.
libpcap	libnl	link with dev-libs/libnl (used to put wireless interfaces in monitor mode)
libproxy	gnome	Enable support for reading proxy settings from GNOME
libproxy	kde	Enable support for reading proxy settings from KDE
libsocialweb	connman	Use net-misc/connman for getting network connection status information
	gnome	Extract proxy information using net-libs/libsoup-gnome
	introspection	Use dev-libs/gobject-introspection for introspection
	vala	Build bindings for dev-lang/vala
libsoup	introspection	Use dev-libs/gobject-introspection for introspection
libsoup	samba	Use net-fs/samba for NTLM Single Sign-On
libsoup-gnome	introspection	Use dev-libs/gobject-introspection for introspection
libsrtp	aesicm	Use AES ICM cryptographic algorithm
	console	Use /dev/console instead of stdout for error messages
	syslog	Use syslog for error messages
libssh	gcrypt	Prefer dev-libs/libgcrypt over dev-libs/openssl for encryption
	pcap	Build with PCAP output support
	server	Build with SSH server support
	sftp	Build with SFTP support
	ssh1	Build with SSH1 support
libssh2	gcrypt	Use dev-libs/libgcrypt for crypto
libvncserver	no24bpp	disable 24bpp support
loudmouth	asyncns	Use libasyncns for asynchronous name resolution.
neon	libproxy	Add support for net-libs/libproxy
neon	pkcs11	Add support for PKCS#11 using dev-libs/pakchois
netembryo	sctp	Support for Stream Control Transmission Protocol
opal	audio	Enable audio support
	capi	Enable CAPI support
	celt	Enable CELT ultra-low delay audio codec
	dtmf	Enable DTMF encoding/decoding support
	fax	Enable T.38 FAX protocol
	h224	Enable H.224 real time control protocol
	h281	Enable H.281 Far-End Camera Control protocol
	h323	Enable H.323 protocol
	iax	Enable Inter-Asterisk eXchange protocol
	ilbc	Enable iLBC (RFC 3951) speech codec
	ivr	Enable Interactive Voice Response
	ixj	Enable xJack cards support
	lid	Enable Line Interface Device
	noaudio	Disable audio codecs
	novideo	Disable video codecs
	plugins	Enable plugins support
	sbc	Enable the Bluetooth low-complexity, SubBand Codec
	sip	Enable Session Initiation Protocol
	sipim	Enable SIP Instant Messages session
	srtp	Enable Secure Real-time Transport Protocol
	stats	Enable statistic reporting
	swig	Use swig to generate bindings
	video	Enable video support
	vpb	Enable Voicetronics VPB card support
	vxml	Enable VXML support
	wav	Enable WAVFILE support
	x264-static	Install x264 plugin statically linked with x264
openh323	noaudio	Disable audio codecs
openh323	novideo	Disable video codecs
ortp	srtp	Add support for Secure RTP
pjsip	epoll	epoll system call support
	ext-sound	External sound device support
	g711	Builds the G711 codec
	g722	Builds the G722 codec
	g7221	Builds the G7221 codec
	ilbc	Builds the ilbc codec
	l16	Builds the L16 codec
ptlib	asn	Enable ASN decoding/encoding support
	audio	Enable audio support
	dtmf	Enable DTMF encoding/decoding support
	http	Enable HTTP support
	mail	Enable mail protocols (POP3/SMTP)
	qos	Enable QOS support
	remote	Enable remote connection support
	serial	Enable serial port support
	shmvideo	Enable shared memory video devices
	socks	Enable SOCKS protocol support
	stun	Enable STUN support
	telnet	Enable telnet protocol support
	tts	Enable Text-To-Speech server support
	video	Enable video support
	vxml	Enable VoiceXML support
	wav	Enable WAVFILE support
qxmpp	extras	Obsolete flag left for compability with leechcraft ebuilds
rest	gnome	Extract proxy information using net-libs/libsoup-gnome
rest	introspection	Use dev-libs/gobject-introspection for introspection
telepathy-glib	introspection	Use dev-libs/gobject-introspection for introspection
telepathy-glib	vala	Enable bindings for dev-lang/vala
telepathy-qt	farsight	Enable support for farsight connection manager
telepathy-qt	glib	Enable support for various telepathy/glib related packages
webkit-gtk	coverage	Enable code coverage support
	introspection	Use dev-libs/gobject-introspection for introspection
	jit	Enable JIT javascript compiler (disabling it will cause performance penalty)
	webgl	Build support for the WebGL HTML API using virtual/opengl
wt	extjs	Build Wt Ext library with JavaScript-only widgets (http://extjs.com/)
	fcgi	Compile in FCGI connector
	graphicsmagick	Enable GraphicsMagick, for supporting painting to raster images (PNG, GIF, ...) (WRasterImage)
	resources	Install resources directory
	server	Compile in stand-alone httpd connector
xrootd	fuse	Enable the sys-fs/fuse filesystem driver
xulrunner	crashreporter	Enable crash reporter for bugs
	custom-optimization	Fine-tune custom compiler optimizations
	gconf	Enable gnome2 gconf support
	ipc	Use inter-process communication between tabs and plugins. Allows for greater stability in case of plugin crashes
	system-sqlite	Use the system-wide dev-db/sqlite installation with secure-delete enabled
	webm	Use system libvpx media-libs/libvpx
zeromq	pgm	0MQ is build with 'Pragmatic General Multicast' (RFC 3208) support using the excellent OpenPGM implementation.

net-mail

Package	Flag	Description
courier-imap	trashquota	include deleted messages, and the Trash folder, in the estimated quota usage for maildirs
cyrus-imapd	replication	Enable replication support in the cyrus imap server
cyrus-imapd	sieve	Enable sieve support
dbmail	sieve	Enable sieve filter support
dovecot	cydir	Add cydir storage support
	dbox	Add dbox storage support
	imapc	Add imap client storage support
	lucene	Add lucene full text search (FTS) support using dev-cpp/clucene
	managesieve	Add managesieve protocol support
	mdbox	Add mdbox storage support
	sdbox	Add sdbox storage support
	sieve	Add sieve support
	vpopmail	Add vpopmail support
fdm	courierauth	Add support for Courier authentication library
fetchmail	hesiod	Enable support for hesiod
	socks	Enable support for socks proxy
	tk	Enable support for Tk GUI toolkit, in particular it installs fetchmailconf
gnubiff	password	Enable save passwords to connect mail servers in user space
hotwayd	smtp	Build SMTP proxy (hotsmtpd)
lbdb	abook	Enables app-misc/abook support
lbdb	finger	Enables finger support
libpst	dii	enable dii support
mailutils	tokyocabinet	Enable Tokyo Cabinet database support
mairix	gnus	Add support for the marks propagation feature in app-emacs/gnus
mu	gui	Build and install the experimental gui 'mug'.
notmuch	crypt	Support decryption and verification of PGP/MIME messages and in Emacs UI - encryption
	doc	Install API documentation for enabled bindings
	emacs	Install Notmuch client for Emacs (main client)
	vim	Install Notmuch client for Vim (experimental)
qmailadmin	maildrop	Filter spam using maildrop
qpopper	apop	Enables the pop.auth file in /etc/pop.auth
	drac	Enables DRAC support
	mailbox	Enables mail spool file is in home directory ~/Mailbox
tpop3d	authexternal	Enable authentication by an external program
	drac	Enable dynamic relay support in the tpop3d pop3 server
	flatfile	Enable authentication against /etc/passwd-style flat files
	passwd	Enable /etc/passwd authentication
	sha1	Use OpenSSL for sha1 encrypted passwords.
	shadow	Enable /etc/shadow authentication
uw-imap	clearpasswd	Enables cleartext logins outside of SSL sessions
vchkuser	debug	Enables debug messages to syslog
vpopmail	clearpasswd	Enables cleartext password storage in the vpasswd files
	ipalias	Enables enable-ip-alias-domains
	maildrop	Enables mail-filter/maildrop support in vdelivermail
	spamassassin	Enables mail-filter/spamassassin support

net-misc

Package	Flag	Description
apt-cacher-ng	fuse	Install the sys-fs/fuse based acngfs, to use a userspace filesystem for the apt cache.
aria2	ares	Enables support for asynchronous DNS using the c-ares library
	bittorrent	Enables support for the bittorrent protocol
	metalink	Enables support for metalink
	scripts	Install additional scripts which use aria2's xmlrpc functionality
asterisk	ais	Support clustering using the Application Interface Specification framework
	dahdi	Support Digium compatible hardware (formerly known as Zaptel).
	gtalk	Enable support for Google Talk services
	http	Enable embedded web server
	newt	Include additional tools that require redhats windowing toolkit
	osplookup	Support secure peering using the Open Settlement Protocol
	samples	Install sample sound and configuration files (default: on)
	span	Enable support for the spandsp codec
	srtp	Enable support for encrypted voice transmission (secure RTP)
asterisk-core-sounds	alaw	Install the sounds files for the alaw codec.
	g722	Install the sounds files for the g722 codec.
	g729	Install the sounds files for the g729 codec.
	gsm	Install the sounds files for the +gsm codec.
	siren14	Install the sounds files for the siren14 codec.
	siren7	Install the sounds files for the siren7 codec.
	sln16	Install the sounds files for the sln16 codec.
	ulaw	Install the sounds files for the ulaw codec.
	wav	Install the sounds files for the wav codec.
asterisk-extra-sounds	alaw	Install the sounds files for the alaw codec.
	g722	Install the sounds files for the g722 codec.
	g729	Install the sounds files for the g729 codec.
	gsm	Install the sounds files for the +gsm codec.
	siren14	Install the sounds files for the siren14 codec.
	siren7	Install the sounds files for the siren7 codec.
	sln16	Install the sounds files for the sln16 codec.
	ulaw	Install the sounds files for the ulaw codec.
	wav	Install the sounds files for the wav codec.
asterisk-moh-opsound	alaw	Install the sounds files for the alaw codec.
	g722	Install the sounds files for the g722 codec.
	g729	Install the sounds files for the g729 codec.
	gsm	Install the sounds files for the +gsm codec.
	siren14	Install the sounds files for the siren14 codec.
	siren7	Install the sounds files for the siren7 codec.
	sln16	Install the sounds files for the sln16 codec.
	ulaw	Install the sounds files for the ulaw codec.
	wav	Install the sounds files for the wav codec.
cfengine	html	Install HTML documentation
	mysql	Use dev-db/mysql as database backend, default would be Berkeley DB (sys-libs/db)
	postgres	Use dev-db/postgresql-server as database backend, default would be Berkeley DB (sys-libs/db)
	qdbm	Use dev-db/qdbm as database backend, default would be Berkeley DB (sys-libs/db)
	tests	Install test files
	tokyocabinet	Use dev-db/tokyocabinet as database backend, default would be Berkeley DB (sys-libs/db)
connman	ethernet	Enable ethernet support.
	google	Enable Google Public DNS support.
	ntpd	Use net-misc/ntp for nptd plugin.
	ofono	Use net-misc/ofono for telephony support.
	openvpn	Use net-misc/openvpn for openvpn support.
	tools	Enable testing tools.
	vpnc	Use net-misc/vpnc for cisco VPN support.
	wimax	Use net-wireless/wimax for WiMAX support.
curl	ares	Enabled c-ares dns support
	gnutls	Prefer gnutls over nss and openssl as the crypto engine
	nss	Prefer NSS over openssl as the crypto engine
	ssh	Enabled SSH urls in curl using libssh2
	ssl	Enable crypto engine support (via openssl if USE='-gnutls -nss')
dahdi	flash	Support (short) flash on FXS
dahdi-tools	ppp	Enables PPP/DAHDIRAS support
dhcp	client	Install the dhclient program
dhcp	server	Install the dhcpd and dhcrelay programs
directvnc	mouse	Adds mouse support
dnetstats	gnome	Use gksu to gain root access
dnetstats	kde	Use kdesu to gain root access
dropbear	bsdpty	Add support for legacy BSD pty's rather than dynamic UNIX pty's -- do not use this flag unless you are absolutely sure you actually want it
dropbear	multicall	Build all the programs as one little binary (to save space)
flexget	deluge	Enable deluge output plugin
flexget	transmission	Enable transmission output plugin
freerdp	debug-assert	Enable assert debugging
	debug-certificate	Enable certificate related debug messages
	debug-chanman	Enable channel manager debug messages
	debug-dvc	Enable dynamic virtual channel debug messages
	debug-gdi	Enable graphics debug messages
	debug-kbd	Enable keyboard related debug messages
	debug-license	Enable license debug messages
	debug-nego	Enable negotiation related debug messages
	debug-nla	Enable authentication related debug messages
	debug-orders	Print drawing orders debug messages
	debug-proto	Enable protocol debugging output
	debug-rail	Enable RemoteApp debug messages
	debug-redir	Print redirection debug messages
	debug-rfx	Enable RemoteFX debug messages
	debug-scard	Print smartcard debug messages
	debug-serial	Enable debugging of serial code
	debug-smartcard	Enable debugging of smard-card code
	debug-sound	Enable debugging of sound code
	debug-stream-assert	Enable stream assert debugging
	debug-svc	Enable static virtual channel debug messages
	debug-transport	Enable transport debug messages
	debug-x11	Enable X11 Client debug messages
	debug-xv	Enable XVideo debug messages
	gnutls	Use GnuTLS as crypto backend
	nss	Use NSS as crypto backend
	polarssl	Use PolarSSL as crypto backend
	ssl	Use OpenSSL as crypto backend
gsasl	gcrypt	Use dev-libs/libgcrypt for low-level crypto
gsasl	ntlm	Add support for Microsoft's NTLM mechanism using net-libs/libntlm
gwget	epiphany	Build epiphany extensions
htbinit	esfq	Add support for Enhanced Stochastic Fairness queueing discipline.
hylafax	html	Adds HTML documentation
hylafax	mgetty	Adds support for mgetty and vgetty
icecast	yp	Build support for yp public directory listings
iputils	SECURITY_HAZARD	Allow non-root users to flood (ping -f). This is generally a very bad idea.
italc	system-libvncserver	Build against the system libvncserver (experimental)
knock	server	Installs the knockd server daemon.
leechcraft-netstoremanager	yandexdisk	Support Yandex.Disk storage backend
mediatomb	inotify	Enable inotify filesystem monitoring support
	lastfm	Enable last.fm support
	libextractor	Use libextractor to gather files' metadata.
	mysql	Use dev-db/mysql as backend rather than SQLite3. If this USE flag is disabled, dev-db/sqlite is used instead.
	taglib	Use media-libs/taglib for reading files' metadata rather than id3lib. If this USE flag is disabled media-libs/id3lib is used instead.
	thumbnail	Enables video thumbnails generation through media-video/ffmpegthumbnailer
memcached	slabs-reassign	Allow manual reassignment of memory slabs at the cost of slab optimizations.
mico	findbug	Adds patch to help finding bug#343827
mulk	checksum	Enable checksum verification for Metalink from dev-libs/openssl
mulk	metalink	Enable support for media-libs/libmetalink
networkmanager	connection-sharing	Use net-dns/dnsmasq and net-firewall/iptables for connection sharing
	dhclient	Use dhclient from net-misc/dhcp for getting ip
	dhcpcd	Use net-misc/dhcpcd for getting ip
	introspection	Use dev-libs/gobject-introspection for introspection
	nss	Use dev-libs/nss for cryptography
	ppp	Enable support for mobile broadband and PPPoE connections using net-dialup/ppp
	resolvconf	Use net-dns/openresolv for managing DNS information
	wimax	Enable support for WiMAX connections using net-wireless/wimax
ntp	openntpd	Allow ntp to be installed alongside openntpd
	parse-clocks	Add support for PARSE clocks
	samba	Provide support for Samba's signing daemon (needed for Active Directory domain controllers)
nxcl	nxclient	Use nxssh from net-misc/nxclient instead of standard ssh
nxserver-freenx	nxclient	Allow to install net-misc/nxclient in parallel with this package, using it to display messages in the sessions
ofono	atmodem	ETSI AT modem support.
	bluetooth	Enable Bluetooth modem support using net-wireless/bluez.
	cdmamodem	Enable CDMA modem support.
	isimodem	Enable PhoNet/ISI modem support.
	phonesim	Enable phone Simulator support
	tools	Enable testing tools
oidentd	masquerade	Enable support for masqueraded/NAT connections
openssh	X509	Adds support for X.509 certificate authentication
	hpn	Enable high performance ssh
	ldap	Add support for storing SSH public keys in LDAP
openswan	curl	Include curl support (used for fetching CRLs)
	extra-algorithms	Include additional strong algorithms (Blowfish, Twofish, Serpent and SHA2)
	ldap	Include LDAP support (used for fetching CRLs)
	ms-bad-proposal	Allow bad IP address proposal offered by an Microsoft L2TP/IPSec servers
	nocrypto-algorithms	Include algorithms that don't even encrypt (1DES)
	nss	Include libnss support (adds smartcard support)
	ssl	Use OpenSSL libraries for BIGNUM support
	weak-algorithms	Include weak algorithms (DH1)
openvpn	eurephia	Apply eurephia patch
	iproute2	Enabled iproute2 support instead of net-tools
	passwordsave	Enables openvpn to save passwords
	pkcs11	Enable PKCS#11 smartcard support
plowshare	scripts	Install some additional helper scripts
plowshare	view-captcha	View captcha with aview
ps3mediaserver	multiuser	Allow renderer customization per-user.
	transcode	Install optional dependencies for transcoding support via media-video/mplayer
	tsmuxer	Install optional dependencies for transcoding support via media-video/tsmuxer
quagga	bgpclassless	Apply unofficial patch to enable classless prefixes for BGP. Patch and information to be found at http://hasso.linux.ee/doku.php/english:network:quagga
	multipath	Enable multipath routes support for any number of routes
	ospfapi	Enable OSPFAPI support for client applications accessing the OSPF link state database
	pam	Add support for PAM (via sys-libs/pam) to the Quagga Virtual Terminal Interface Shell (vtysh); if the readline USE flag is disabled, this flag is ignored.
	readline	Enable support for sys-libs/readline to provide the Quagga Virtual Terminal Interface Shell (vtysh).
	tcp-zebra	Enable TCP zserv interface on port 2600 for Zebra/protocol-daemon communication. Unix domain sockets are chosen otherwise.
rdesktop	pcsc-lite	Enable smartcard support with sys-apps/pcsc-lite driver
remmina	ssh	Enable support for SSH/SFTP using net-libs/libssh
	unique	Enable single instance support using dev-libs/libunique
	vte	Enable Terminal support using x11-libs/vte
	xdmcp	Enable support for X Display Manager Control Protocol
remmina-plugins	nx	Enable support for NX protocol
	ssh	Enable support for SSH protocol
	telepathy	Enable telepathy support
	xdmcp	Use Xephyr for XDMCP protocol
rygel	tracker	Install dependencies for the tracker plugin
rygel	transcode	Install dependencies for transcoding support
scponly	gftp	Enables gFTP compatibility
	logging	Enables SFTP logging compatibility
	passwd	Enables passwd compatibility
	quota	Enables quota compatibility
	rsync	Enables rsync compatibility with potential security risks
	scp	Enables scp compatibility with potential security risks
	sftp	Enables SFTP compatibility
	subversion	Enables Subversion compatibility with potential security risks
	unison	Enables Unison compatibility with potential security risks
	wildcards	Enables wildcard processing with potential security risks
	winscp	Enables WinSCP 2.0 compatibility with potential security risks
sitecopy	rsh	This allows the use of rsh (remote shell) and rcp (remote copy) for authoring websites. sftp is a much more secure protocol and is preferred.
sitecopy	webdav	Enable WebDav (Web-based Distributed Authoring and Versioning) support. This system allows users to collaborate on websites using a web based interface. See the ebuild for an FAQ page. Enables neon as well to handle webdav support.
slimrat	X	Install also GUI client
spice-gtk	gtk3	Link against x11-libs/gtk+:3 instead of x11-libs/gtk+:2
	introspection	Use dev-libs/gobject-introspection for introspection
	policykit	Enable sys-auth/polkit support for the usbredir acl helper
	usbredir	Use sys-apps/usbredir to redirect USB devices to another machine over TCP
	vala	Generate dev-lang/vala bindings using vapigen and regenerate .vala files using valac
streamtuner	shout	Enable shoutcast plug-in.
streamtuner	xiph	Enable xiph.org plug-in.
strongswan	cisco	Enable support for the Cisco VPN client.
	dhcp	Enable server support for querying virtual IP addresses for clients from a DHCP server. (IKEv2 only)
	eap	Enable support for the different EAP modules that is supported.
	farp	Enable faking of ARP responses for virtual IP addresses assigned to clients. (IKEv2 only)
	gcrypt	Enable dev-libs/libgcrypt plugin which provides 3DES, AES, Blowfish, Camellia, CAST, DES, Serpent and Twofish ciphers along with MD4, MD5 and SHA1/2 hash algorithms, RSA and DH groups 1,2,5,14-18 and 22-24(4.4+). Also includes a software random number generator.
	ikev1	Enable IKEv1 protocol (pluto daemon).
	ikev2	Enable IKEv2 protocol (charon daemon).
	nat-transport	Enable potentially insecure NAT traversal for transport mode in IKEv1. Only enable if you really need this.
	non-root	Force IKEv1/IKEv2 daemons to normal user privileges. This might impose some restrictions mainly to the IKEv1 daemon. Disable only if you really require superuser privileges.
	openssl	Enable dev-libs/openssl plugin which is required for Elliptic Curve Cryptography (DH groups 19-21,25,26) and ECDSA. Also provides 3DES, AES, Blowfish, Camellia, CAST, DES, IDEA and RC5 ciphers along with MD2, MD4, MD5 and SHA1/2 hash algorithms, RSA and DH groups 1,2,5,14-18 and 22-24(4.4+) dev-libs/openssl has to be compiled with USE="-bindist".
stunnel	listen-queue	Enable Listen Queue support for Stunnel
stunnel	xforward	Enable X-Forwarded-For support for Stunnel
termpkg	uucp	Adds support for uucp style device locking
tigervnc	server	Build TigerVNC server
tigervnc	xorgmodule	Build the Xorg module
tightvnc	server	Build vncserver. Allows us to only build server on one machine if set, build only viewer otherwise.
tinc	raw	Enable support for Raw Sockets
	uml	Enable support for User Mode Linux Sockets
	vde	Enable Virtual Distributed Ethernet (VDE) based networking
tor	bufferevents	Use Libevent's buffered IO
	nat-pmp	Enable NAT Port Mapping Protocol
	tor-hardening	Compile tor with hardening on vanilla compilers/linkers
	transparent-proxy	Enable transparent proxying
	upnp	Enable Universal Plug and Play
vde	pcap	Enable the pcap-based plugin that allows creating a switch against a real interface.
vde	ssl	Enable the cryptcab plugin that allows creating an encrypted virtual cable.
vidalia	tor	Allow to use a local tor setup
vinagre	applet	Enable vinagre applet for gnome-base/gnome-panel
	ssh	Enable ssh plugin using x11-libs/vte
	telepathy	Enable access to remote desktop via a net-libs/telepathy-glib client
vino	telepathy	Enable desktop sharing through a telepathy client
vpnc	hybrid-auth	Enable hybrid authentication (certificates), only if not redistributed as compiled binary
	openssl	Use dev-libs/openssl for hybrid-auth instead of net-libs/gnutls, may cause license issues when redistributing.
	resolvconf	Enable support for DNS managing framework net-dns/openresolv
wget	ntlm	Enable support for NTLM (Windows-based) authorization
wicd	gtk	Installs a gtk UI. This is enabled by default because it is intended behavior. Requires dev-python/pygtk
	ioctl	Installs additional python libraries to use as a backend. This will improve speed but is experimental.
	mac4lin	Change default icons to mac4lin icon set
	ncurses	Installs a ncurses UI
	pm-utils	Installs the pm-utils hooks for suspend/resume and requires sys-power/pm-utils
x2goserver	fuse	Use sys-fs/sshfs-fuse to allow shared folders
yaydl	soundextract	Extract the soundtracks of the downloaded videos

net-nds

Package	Flag	Description
389-ds-base	auto-dn-suffix	Enable auto bind with auto dn suffix over unix domain socket (LDAPI) support
	autobind	Enable auto bind over unix domain socket (LDAPI) support
	bitwise	Enable bitwise plugin - supported data in raw/bitwise format
	dna	Enable dna (distributed numeric assignment ) plugin - to automatically assign unique uid numbers to new user entries as they are created.
	ldapi	Enable LDAP over unix domain socket (LDAPI) support
	pam-passthru	Enable pam-passthru plugin - for simple and fast system services used in ldap
	presence	Enable presence plugin - non-stabdart syntax validation
gosa-core	mail	Manage mail accounts and servers with gosa.
gosa-core	samba	Manage samba accounts with gosa.
nsscache	nsscache	Depend on sys-auth/libnss-cache to handle flat files
nsscache	nssdb	Depend on sys-libs/libnss_db to handle dbm files.
openldap	experimental	Enable experimental backend options
	odbc	Enable ODBC and SQL backend options
	overlays	Enable contributed OpenLDAP overlays
	smbkrb5passwd	Enable overlay for syncing ldap, unix and lanman passwords
tac_plus	finger	Adds support for checking user counts via fingering the NAS
tac_plus	maxsess	Enforce a limit on maximum sessions per user

net-news

Package	Flag	Description
liferea	ayatana	Build in support for Ayatana notification using the libindicate plugin.
	libnotify	Enable popup notifications
	lua	Enable lua scripting

net-nntp

Package	Flag	Description
inn	innkeywords	Enable automatic keyword generation support
inn	inntaggedhash	Use tagged hash table for history (disables large file support)
nzbget	parcheck	Enable support for checking PAR archives
slrn	canlock	Add support for cancel locks via net-libs/canlock
slrn	uudeview	Add support for yEnc coding and more using dev-libs/uulib
tin	cancel-locks	Enable Cancel-Lock header functionality (also enables USE=evil)
	etiquette	Enable the display off posting etiquettes
	evil	Let tin generate a message ID
	forgery	Cancel messages posted from a different account
	gpg	Enable app-crypt/gpg support

net-p2p

Package	Flag	Description
amule	daemon	Enable amule daemon
	remote	Enable remote controlling of the client
	stats	Enable statistic reporting
	upnp	Enables support for Intel UPnP stack.
bitcoin-qt	eligius	Enable using lower fees accepted by Eligius
bitcoin-qt	upnp	Enable Universal Plug and Play
bitcoind	eligius	Enable using lower fees accepted by Eligius
bitcoind	upnp	Enable Universal Plug and Play
dbhub	switch_user	Enable support for switching user
deluge	webinterface	Install dependencies needed for the web interface
eiskaltdcpp	cli	Enable eiskaltdcpp-daemon with sample cli based on readline
	daemon	Enable eiskaltdcpp-daemon without any UI
	dht	Enable DHT (distributed hash table) support for libeiskaltdcpp
	emoticons	Install emoticon packs
	minimal	Don't install headers
	upnp	Forward ports using UPnP
fms	frost	Add support for frost boards
freenet	freemail	Add Freemail support
gift	ares	pull in Ares plugin
	fasttrack	pull in FastTrack plugin
	gnutella	pull in Gnutella plugin
	openft	pull in OpenFT plugin
gnunet	ares	enable asynchronous dns support through net-dns/c-ares library
	gtk	enable gtk setup wizard
	microhttpd	enable embedded http server support
	mysql	enable mysql database backend
	ncurses	enable ncurses setup wizard using dev-util/dialog
	qt4	enable qt4 setup wizard
	setup	enable setup wizard
	smtp	enable SMTP support using net-libs/libesmtp
	sqlite	enable sqlite database backend
ktorrent	bwscheduler	Schedule upload and download limits over a period of a week
	downloadorder	Specify the download order of a multi-file torrent
	infowidget	Displays general information about a torrent in several tabs
	ipfilter	Filter IP addresses through a blocklist
	kross	Enable kross scripting support
	logviewer	Displays the logging output
	magnetgenerator	Generates magnet URI's
	mediaplayer	Phonon-based media player
	rss	Syndication plugin for KTorrent, supporting RSS and Atom feeds
	scanfolder	Scan folders for torrent files and load them
	search	Search for torrents
	shutdown	Shutdown when done
	stats	Shows statistics about torrents in several graphs
	upnp	Forward ports using UPnP
	webinterface	Allows control of KTorrent via a web interface
	zeroconf	Discover peers on the local network using the Zeroconf protocol
leechcraft-eiskaltdcpp	emoticons	Install emoticon packs
leechcraft-eiskaltdcpp	upnp	Forward ports using UPnP
mldonkey	bittorrent	enable bittorrent support
	fasttrack	enable fasttrack support
	gnutella	enable gnutella and gnutella2 support
	guionly	enable client build only
	magic	enable use of libmagic
rtorrent	color	Add custom color support for torrent list
rtorrent	daemon	Uses app-misc/screen to daemonize this application
transmission	ayatana	Enable Ayatana support with dev-libs/libappindicator
	libcanberra	Enable sound event support with media-libs/libcanberra
	utp	Adds support for µTP (Micro Transport Protocol)
transmission-remote-gtk	libproxy	Use net-libs/libproxy for getting the HTTP/HTTPS/SOCKS proxy configuration.
transmission-remote-gtk	unique	Enable single instance support using dev-libs/libunique

net-print

Package	Flag	Description
cups	filters	Pull in net-print/foomatic-filters for filtering by default.
	java	Add support for the Java interpeter in the web server CGIs.
	perl	Add support for the Perl interpeter in the web server CGIs.
	php	Add support for the PHP interpeter in the web server CGIs.
	python	Add support for the Python interpeter in the web server CGIs.
fax4cups	capisuite-fax	Install net-dialup/capisuite backend
	efax	Install net-misc/efax backend
	hylafax	Install net-misc/hylafax backend
	mgetty-fax	Install net-dialup/mgetty backend
hplip	X	Enables scanner GUI dependencies with USE="scanner" where media-gfx/xsane is preferred over media-gfx/sane-frontends
	acl	Install udev acl rules which needs sys-fs/udev with acl support
	doc	Build documentation
	fax	Enable fax on multifunction devices which support it
	hpcups	Build the hpcups driver for cups (by HP)
	hpijs	Build the IJS driver for cups (Foomatic)
	kde	Enables kde-misc/skanlite as scanner GUI with USE="scanner X"
	libnotify	Enables desktop notifications
	minimal	Only build internal hpijs/hpcups driver (not recommended at all, make sure you know what you are doing)
	parport	Enable parallel port for devices which require it
	qt4	Enable graphical interface using Qt 4
	scanner	Enable scanner on multifunction devices which support it
	snmp	Add support for net-analyzer/net-snmp which enables this driver to work over networks (both for server and client)
	static-ppds	Use statically-generated PPDs instead of Dynamic PPDs. Although this is deprecated some printers may still need it to work properly. Use this flag if hp-setup fails to find/create a valid PPD file
magicfilter	lprng-failsafe	Refuse options for compability with certain LPRng versions.
pkpgcounter	psyco	psyco python accelerator

net-proxy

Package	Flag	Description
dansguardian	kaspersky	Adds support for Kaspersky AntiVirus software
dansguardian	ntlm	Enable support for the NTLM auth plugin
squid	ecap	Adds support for loadable content adaptation modules (http://www.e-cap.org)
	epoll	Enables Linux epoll() support
	icap-client	Adds ICAP client support
	ipf-transparent	Adds transparent proxy support for systems using IP-Filter (only for *bsd)
	kqueue	Enables *BSD kqueue() support
	logrotate	Use app-admin/logrotate for rotating logs
	pf-transparent	Adds transparent proxy support for systems using PF (only for *bsd)
	tproxy	Enables real Transparent Proxy support for Linux Netfilter TPROXY
	zero-penalty-hit	Add Zero Penalty Hit patch (http://zph.bratcheda.org)
sshproxy	client-only	Install only the client wrappers
tinyproxy	filter-proxy	Enable filtering of domains/URLS
	reverse-proxy	Enable reverse proxying
	transparent-proxy	Enable transparent proxying
	upstream-proxy	Enable upstream proxying
	xtinyproxy-header	Include the X-Tinyproxy header
tsocks	tordns	Apply tordns patch which allows transparent TORification of the DNS queries
ufdbguard	doc	Download and install the ufdbguard reference manual in PDF.
ufdbguard	httpd	Build, install and start the provided mini-http daemon with the redirect CGI integrated. Since there is no way to tell ufdbguard to not start it, this is a build-time option.

net-voip

Package	Flag	Description
ekiga	gconf	Enable GConf support
	h323	Enable H.323 protocol
	shm	Enable the Shared Memory Extension from libXext
	static	Statically link to opal and ptlib
	xcap	Enable XML Configuration Access Protocal
linphone	video	Enable video support (display/capture)
sflphone	doxygen	Support for building documentation with doxygen
sflphone	iax	Support for IAX (Inter Asterisk eXchange)
yate	h323	Build H.323 Channel plugin
	ilbc	Build ILBC codec plugin
	sctp	Support for Stream Control Transmission Protocol
	spandsp	Enable support for the spandsp codec

net-wireless

Package	Flag	Description
blueman	network	Add functionality to setup (host) PAN connections using either net-dns/dnsmasq or net-misc/dhcp
bluez	consolekit	Use sys-auth/pambase[consolekit] to determine access to bluetooth devices based on whether a user is logged in locally or remotely
	health	Compile with initial support for HDP
	maemo6	Compile with maemo6 plugin
	old-daemons	Install old daemons like hidd and sdpd that are deprecated by the new Service framework
	pnat	Enable pnat plugin
	test-programs	Install tools for testing of various Bluetooth functions
gnome-bluetooth	introspection	Use dev-libs/gobject-introspection for introspection
	nautilus	Build the gnome-extra/nautilus-sendto plugin
	sendto	Build the gnome-extra/nautilus-sendto plugin
hostapd	debug	Enables debugging
	logwatch	Install support files for sys-app/logwatch
	madwifi	Add support for madwifi (Atheros chipset)
	wps	Add support for Wi-Fi Protected Setup
kismet	client	Build the ncurses-based user interface
	pcap	Enable packet capturing support using net-libs/libpcap
	suid	Install a setuid root helper binary with limited functionality; this allows running kismet as a normal user, significantly reducing security risks
madwifi-ng	injection	Adds support for net-wireless/aircrack-ng aireplay-ng packet injection
wepattack	john	Build with app-crypt/johntheripper support
wifiscanner	wireshark	Use the net-analyzer/wireshark wtap library
wireless-tools	multicall	Build the most commonly used tools as one binary
wpa_supplicant	eap-sim	Add support for EAP-SIM authentication algorithm
	fasteap	Add support for FAST-EAP authentication algorithm
	madwifi	Add support for madwifi (Atheros chipset)
	ps3	Add support for ps3 hypervisor driven gelic wifi
	wimax	Add support for Wimax EAP-PEER authentication algorithm
	wps	Add support for Wi-Fi Protected Setup

rox-base

Package	Flag	Description
rox	video	Enable rox-extra/videothumbnail for creating thumbnails of videos with mplayer or totem.

rox-extra

Package	Flag	Description
archive	ace	Enable .ace extraction via app-arch/unace
	compress	Enable tar.Z and *.Z extraction via app-arch/ncompress
	cpio	Enable .cpio extraction via app-arch/cpio
	rar	Enable .rar extraction via app-arch/unrar
	rpm	Enable .rpm extraction via rpm2cpio from app-arch/rpm
	uuencode	Enable .uue extraction via app-arch/sharutils
	zip	Enable .zip extraction via app-arch/unzip and app-arch/zip
comicthumb	rar	Enable support for rar-compressed archives via app-arch/unrar
magickthumbnail	xcf	Enable previews of .xcf files using media-gfx/gimp

sci-astronomy

Package	Flag	Description
cpl	gasgano	Enable support for sci-astronomy/gasgano file organizer
predict	xforms	Add a "map" client which uses the x11-libs/xforms library for its GUI
predict	xplanet	Project predict data onto world maps generated by x11-misc/xplanet / x11-misc/xearth
scamp	plplot	Build with sci-libs/plplot to allow diagnostic plots during processing
stellarium	stars	Install extra star catalogs
wcslib	fits	Enable support for the FITS format through sci-libs/cfitsio
wcslib	pgplot	Builds routines for the sci-libs/pgplot library

sci-biology

Package	Flag	Description
amos	qt	Compile the hawkeye assembly viewer
bioperl	db	Install sci-biology/bioperl-run
	network	Install sci-biology/bioperl-run
	run	Install sci-biology/bioperl-run
clustalw-mpi	mpi_njtree	Use MPI (as opposed to serial) code for computing neighbor-joining trees
clustalw-mpi	static_pairalign	Use static (as opposed to dynamic) scheduling for pair alignments
exonerate	utils	Install all utilities
fasta	icc	Use intel compiler instead of gcc
gmap	goby	Enable support for goby
gmap	samtools	Enable support for samtools
goby	cpp	Compile C/C++ API
hmmer	pvm	Add support for parallel virtual machine (sys-cluster/pvm)
mcl	blast	add support for NCBI BLAST data
plink	R	add support R language
plink	webcheck	add support for online update checking every time the program starts
raxml	sse3	Enable optimization for SSE3 capable chips
tophat	bam	Compile support for the BAM format
ucsc-genome-browser	server	Install genome browser Web application. If this flag is off, only libraries and utilities from the suite are installed.
yass	dmalloc	Enable debugging with the dmalloc library
yass	lowmem	Build for environments with low amounts of memory

sci-chemistry

Package	Flag	Description
PyMca	matplotlib	Support for plotting through matplotlib
apbs	arpack	Include support for arpack libs
	fetk	Include support for FeTK
	tools	Install optional tools
avogadro	glsl	Enable glsl features via GLEW.
ccp4	arpwarp	Add binary arp-warp for molecular replacement
ccp4	balbes	Install sci-chemistry/balbes
ccpn	extendnmr	Install needed packages for extendNMR support
chemtool	emf	EMF export support
cns	aria	Support patch for sci-chemistry/aria
eden	double-precision	More precise calculations at the expense of speed
gamess	neo	Enable NEO for nuclear basis support
	pax_kernel	Make this package work on PAX kernels
	qmmm-tinker	Enable tinker qmmm code
ghemical	openbabel	Use sci-chemistry/openbabel for file conversions
ghemical	toolbar	Build the shortcuts toolbar
gromacs	dmalloc	Enable use of Debug Malloc
	double-precision	More precise calculations at the expense of speed
	fkernels	Enable building of Fortran Kernels for platforms that dont have assembly loops
	single-precision	Single precision version of gromacs
gsim	emf	Support for .emf export
icm	32bit	Automatically generated description for 32bit
icm	64bit	Automatically generated description for 64bit
jmol	client-only	Install the viewer only, no applet files for httpd
mopac7	gmxmopac7	Add support library for gromacs
oasis	minimal	Restricts functionality on free software
openbabel	swig	Use swig to rebuild language bindings.
pdb2pqr	opal	Add web interface via opal
pdb2pqr	pdb2pka	Install experimental pdb2pka interface
pymol	apbs	Install the apbs plugin
	numpy	Compile numpy support
	shaders	Build with Shaders support - good for high-end 3D video cards.
	vmd	Enable vmd module for trajectories
	web	Install Pymodule needed for web app support
raster3d	gd	libgd support for PNG and JPEG output
shelx	dosformat	Use CR/LF to end lines; useful in mixed Linux/Windows environments
vmd	cuda	Use nvidia cuda toolkit for speeding up computations
	msms	Add support for MSMS SAS calcualtion tool
	povray	Add support for povray raytracer for HQ images
	tachyon	Add support for tachyon raytracer for HQ images
votca-csg	extras	Pull in extra applications from sci-chemistry/votca-csg-apps
	gromacs	Add support for gromacs file formats through sci-chemistry/gromacs
	system-boost	Use system boost (dev-libs/boost) instead of bundled one
wxmacmolplt	flash	Add support for flash movie generation using media-libs/ming

sci-electronics

Package	Flag	Description
geda	stroke	enable mouse gesture support
gerbv	unit-mm	Set default unit for coordinates in status bar to mm
gspiceui	schematics	Use sci-electronics/geda for schematics editing
gspiceui	waveform	Use sci-electronics/gwave for waveform display
gtkwave	fasttree	Enables experimental Fast SST Tree widget code.
	fatlines	Renders lines as double width in gtkwave.
	judy	Enables Judy array support.
kicad	dev-doc	Install developer documentation (requires app-doc/doxygen)
pcb	gcode	gcode file export
	gif	GIF graphics export
	jpeg	JPEG graphics export
	m4lib-png	Enable creating png previews for the m4 library
	nelma	NELMA file export
	png	PNG graphics export
	tk	Build tcl/tk graphical QFP footprint generator
	toporouter	Build toporouter
	xrender	Translucent PCB display for Motif/Lesstif GUI

sci-geosciences

Package	Flag	Description
gmt	gmtfull	Full resolution bathymetry database
	gmthigh	Add high resolution bathymetry database
	gmtsuppl	Supplement functions for GMT
	gmttria	Non GNU triangulation method, more efficient
	metric	Use SI (cm) units instead of US (inches) ones
	mex	Enable compilation of mex supplement which requires Octave/Matlab
	octave	Enable octave support
	ps	Enable rendering EPS files
googleearth	mdns-bundled	Use bundled nss-mdns library instead of depending on sys-auth/nss-mdns. Enable this if you want to avoid the deptree.
googleearth	qt-bundled	Use bundled Qt4 libraries instead of system ones. Recommended only for troubleshooting.
gpsd	dbus	export gpsd data over dbus connections
	ntp	Enable net-misc/ntp shared memory interface and PPS kernel support for GPS time
	shm	export gpsd over shared memory
	sockets	export gpsd over unix sockets
grass	gmath	Enable gmath wrapper for BLAS/Lapack (virtual/blas, virtual/lapack)
gshhs	data	Add earth data with sci-geosciences/gshhs-data
mapnik	gdal	Enable sci-libs/gdal library support
	geos	Enable sci-libs/geos library support
	nobfonts	Enable Dejavu fonts instead of built-in fonts
mapserver	gdal	Enable sci-libs/gdal library support
	geos	Enable sci-libs/geos library support
	postgis	Enable dev-db/postgis support
	proj	Enable sci-libs/proj library support (geographic projections)
	xslt	Enable xslt and exslt support xml-mapfile support
merkaartor	libproxy	Use net-libs/libproxy for getting the HTTP/HTTPS/SOCKS proxy configuration
merkaartor	webkit	Enable Webkit browser plugin using x11-libs/qt-webkit
opencpn	gpsd	Add support for using a GPS device through the GPSD deamon
qgis	grass	Add support for sci-geosciences/grass
qgis	spatialite	Enable Spatial DBMS over sqlite dev-db/spatialite

sci-libs

Package	Flag	Description
acml	gfortran	Fetch and install acml compiled with GNU gfortran
	ifc	Fetch and install acml compiled with Intel Fortran Compiler (dev-lang/ifc)
	int64	Install the 64 bits integer library
armadillo	atlas	Link with ATLAS libraries for cblas and clapack (needs sci-libs/lapack-atlas)
arprec	qd	Use sci-libs/qd
cholmod	metis	Enable the Partition module to cholmod using metis (sci-libs/metis, sci-libs/parmetis)
cholmod	supernodal	Enable the Supernodal module (needs virtual/lapack)
fftw	float	Link default library to single precision instead of double (symlinks only and fftw-2.1)
flann	octave	Add bindings for sci-mathematics/octave
gdal	aux_xml	Enable Portable Auxilliary Metadata generation
	ecwj2k	Enable support for alternate jpeg2k library sci-libs/libecwj2
	fits	Enable support for NASA's sci-libs/cfitsio library
	geos	Add support for geometry engine (sci-libs/geos
	gml	Enable support for dev-libs/xerces-c C++ API
	hdf	Add support for the Hierarchical Data Format v. 4 (sci-libs/hdf)
	ogdi	Enable support for the open geographic datastore interface (sci-libs/ogdi)
getdata	fortran	Build fortran bindings
getdata	python	Build python bindings
gsl	cblas-external	Link gsl with external cblas provided by (virtual/cblas) instead of shipped internal version
hdf5	fortran2003	enable new features that require Fortran 2003 (http://www.hdfgroup.org/HDF5/doc/fortran/NewFeatures_F2003.pdf)
indilib	fits	Enable support for the FITS image format through cfitsio
indilib	nova	Enable support for nova celestial mechanics calculations
libcmatrix	atlas	Use of atlas blas implementation
libghemical	mopac7	Use sci-chemistry/mopac7 for semi-empirical calculations
libghemical	mpqc	Use sci-chemistry/mpqc for quantum-mechanical calculations
libsvm	tools	Install python based tool scripts
linux-gpib	firmware	Install firmware
lis	fma	Use the Fused Multiply Add instruction set (x86 arches)
	quad	Enable quadruple precision operations
	saamg	Build the Smoothed Aggregation Algebraic MultiGrid preconditioner
mathgl	octave	Add bindings for sci-mathematics/octave
metis	int64	Build the 64 bits integer library (metis >=5 only)
mkl	fortran95	Installs the BLAS/LAPACK FORTRAN95 static libraries
	int64	Installs the 64 bits integer libraries
	serial	Installs the serial (as non-threaded) libraries
mpir	cpudetection	Enables runtime cpudetection (useful for bindist, compatability on other CPUs)
netcdf	dap	Support for remote data access with the built-in OPeNDAP client
nlopt	octave	Add plugin for sci-mathematics/octave
opencascade	gl2ps	Use gl2ps PostScript printing library
plplot	ada	Add bindings for the ADA programming language
	d	Add bindings for the D programming language
	dynamic	Build with dynamic drivers
	octave	Add bindings for sci-mathematics/octave
	qhull	Add bindings for media-libs/qhull bindings
scipy	umfpack	Adds support for sparse solving with sci-libs/umfpack
spqr	metis	Use METIS (sci-libs/metis or sci-libs/parmetis) for partitioning
spqr	tbb	Enable multithreading with the Intel Threads Building Block (needs dev-cpp/tbb)
spr	root	Add sci-physics/root graphics and i/o support
suitesparse	metis	Use METIS (sci-libs/metis or sci-libs/parmetis) for partitioning
taucs	cilk	Enable multithreading using dev-lang/cilk)
umfpack	metis	Use METIS via CHOLMOD(sci-libs/cholmod) for partitioning
votca-tools	system-boost	Use system boost (dev-libs/boost) instead of bundled one
vtk	R	Enable support for dev-lang/R
	boost	Add support for boost
	cg	Use nvidia's cg shaders
	patented	Build patented classes

sci-mathematics

Package	Flag	Description
Macaulay2	optimization	Accept upstream's choices for -O option, i.e. -O3 almost everywhere.
agda	epic	Add support for the epic compiler.
cgal	mpfi	Enable support for multiple recision interval arithmetic via sci-mathematics/mpfi
dataplot	gs	Add Ghostscript support (app-text/ghostscript-gpl)
freemat	arpack	Add sparse eigen value support via sci-libs/arpack
	ffcall	Enable use of dev-libs/ffcall
	umfpack	Add sparse solving via sci-libs/umfpack
	volpack	Add volume rendering via media-libs/volpack
fricas	clisp	Add support for GNU CLISP (dev-lisp/clisp)
	clozurecl	Add support for Clozure Common Lisp (dev-lisp/closurecl)
	cmucl	Add support for CMU Common Lisp (dev-lisp/cmucl)
	ecl	Add support for Embeddable Common Lisp (dev-lisp/ecls)
	gcl	Add support for GNU Common Lisp (dev-lisp/gcl)
	sbcl	Add support for Steel Bank Common Lisp (dev-lisp/sbcl)
geomview	avg	Enable experimental motion averaging technique
geomview	netpbm	Add media-libs/netpbm support for external modules
gretl	R	Enable support for dev-lang/R
	gtk3	Use GTK+3 frontend instead of GTK+2
	sourceview	Enable support for x11-libs/gtksourceview
isabelle	CCL	CCL (Classical Computational Logic)
	CTT	CTT (Constructive Type Theory) is an extensional version of Martin-Löf's Type Theory.
	Cube	Cube (The Lambda Cube)
	FOL	FOL (Many-sorted First-Order Logic) provides basic classical and intuitionistic first-order logic. It is polymorphic.
	FOLP	FOLP (FOL with Proof Terms)
	HOL	(Higher-Order Logic) is a version of classical higher-order logic resembling that of the HOL System.
	LCF	LCF (Logic of Computable Functions)
	Pure	Pure is the basis for all object-logics.
	Sequents	Sequents (first-order, modal and linear logics)
	ZF	ZF (Set Theory) offers a formulation of Zermelo-Fraenkel set theory on top of FOL.
	graphbrowsing	Generate theory browsing information, including HTML documents that show a theory's definition, the theorems proved in its ML file and the relationship with its ancestors and descendants.
	proofgeneral	Add support for the app-emacs/proofgeneral proof assistant front end.
maxima	clisp	Compile maxima with GNU CLISP (dev-lisp/clisp)
	clozurecl	Compile maxima with Clozure Common Lisp (dev-lisp/clozurecl)
	cmucl	Compile maxima with CMU Common Lisp (dev-lisp/cmucl)
	ecls	Compile maxima with Embeddable Common Lisp (dev-lisp/ecls)
	gcl	Compile maxima with GNU Common Lisp (dev-lisp/gcl)
	sbcl	Compile maxima with Steel Bank Common Lisp (dev-lisp/sbcl)
minisat	extended-solver	Build extended version of SAT solver with additional features.
normaliz	extras	Install sci-mathematics/Macaulay2 and sci-mathematics/singular packages as shipped by upstream
nusmv	minisat	Enable support for MiniSat
octave	glpk	Add support for sci-libs/glpk for linear programming
	qhull	Add support for sci-libs/qhull, to allow `delaunay', `convhull', and related functions
	qrupdate	Add support for sci-libs/qrupdatefor QR and Cholesky update functions.
	sparse	Add enhanced support for sparse matrix algebra
pari	data	Add additional data (elldata, galdata, seadata, nftables)
polymake	libpolymake	Build the polymake library to build applications using the C++ interface.
singular	boost	Compile against external boost headers (dev-libs/boost)
unuran	prng	Use sci-mathematics/prng library
unuran	rngstreams	Use sci-mathematics/rngstreams library
yacas	server	Build the network server version

sci-misc

Package	Flag	Description
boinc	cuda	Use nvidia cuda toolkit for speeding up computations. NOTE: works only for subset of nvidia graphic cards so make sure your card is supported before opening bug about it.
h5utils	hdf	Build hdf to hdf5 (and vice-versa) converter
h5utils	octave	Build Octave plugins
nco	dap	Support for remote data access with the NETCDF DAP client
	ncap2	Build next generation netcdf arithmetic processor (needs dev-java/antlr)
	udunits	Add sci-libs/udunits files support
ncview	udunits	Add sci-libs/udunits files support

sci-physics

Package	Flag	Description
abinit	plugins	Build all plugins
bullet	double-precision	Build libraries in double precision
bullet	extras	Build additional libraries
cernlib-montecarlo	herwig	Build Herwig internal event generator, newer version available in sci-physics/herwig
clhep	exceptions	Enable zoom exceptions for user intervention
espresso	examples	Installs the examples
espresso	packages	Installs extra subpackages
fastjet	cgal	Use sci-mathematics/cgal instead of bundled algorithms
fastjet	plugins	Build all standard and C++ plugins
geant	aida	Add support for Abstract Interfaces for Data Analysis
	athena	Enable the MIT Athena (x11-libs/libXaw) widget set (default is Motif)
	data	Add a lot of standard physics data files for geant4
	dawn	Add support for media-gfx/dawn (3D postscript rendering)
	gdml	Enable geometry markup language for xml
	geant3	Add compatibility for geant321 to geant4
	global	Produce a huge global library instead of small ones
	granular	Produce many small libraries instead of global ones
	openinventor	Add support for media-libs/openinventor SGI toolkit
	raytracerx	Enable raytracing for physics events
	vrml	Enable output of geant4 in vrml formats
hepmc	cm	Build with cm instead of default mm for length units
hepmc	gev	Build with GeV instead of default MeV for momentum units
lhapdf	octave	Add bindings for sci-mathematics/octave
pythia	hepmc	Adds support for High Energy Physics Monte Carlo Generators sci-physics/hepmc
root	clarens	Build the Clarens and PEAC plug-ins, to use in a GRID enabled analysis
	fits	Support for images and data from FITS files with sci-libs/cfitsio
	geant4	Support for sci-physics/geant version 4
	llvm	Build the new cling interactive interpreter based on sys-devel/llvm
	math	Build all math related libraries plugins, needs sci-libs/gsl
	pythia6	Build the interface for sci-physics/pythia version 6.x
	pythia8	Build the interface for sci-physics/pythia version 8.x
	reflex	Build the reflection database for the C++ interpreter
	xrootd	Build the interface for net-libs/xrootd

sci-visualization

Package	Flag	Description
gnuplot	bitmap	Enable dot-matrix printers and pbm terminal
	gd	Add support for media-libs/gd. Needed for GIF, JPEG, and PNG image output.
	thin-splines	Enable thin plate splines
gwyddion	sourceview	Enable support for x11-libs/gtksourceview
hippodraw	fits	Enable HippoDraw's built-in support for reading FITS files, by using the CFITSIO library. FITS binary and ASCII tables are supported as well as images. When combine with numpy flag, it can also use the pyfits package.
	numpy	Enable support for the numerical array manipulation and computational capabilities of numpy in python. HippoDraw can return a numerical array to Python from any of the type of objects that are supported. One can also import data to a HippoDraw from a numpy array.
	root	Adds support for ROOT input/ouput system, storing a table of data as TBranch objects each with a single TLeaf. Files of this type can be imported by HippoDraw as a RootNTuple. Also if root flag is selected, it can use root::minuit for minimization instead of standalone minuit library.
	wcs	Adds 10 built-in transforms to HippoDraw via the World Coordinate System library for FITS files.
opendx	cdf	Add support for sci-libs/cdf data exchange format
opendx	hdf	Add support for the Hierarchical Data Format (sci-libs/hdf)
paraview	boost	Enable the usage of dev-libs/boost
	cg	Add support for nvidia's cg shaders
	gui	Build paraview's gui not just the server
	overview	Enable the OverView plugin framework
	plugins	Build and install additional plugins
	streaming	Enable streaming paraview application
qtiplot	emf	Export support for Windows Enhanced Metafile
	ods	Import support for OpenOffice .ods sheets
	origin	Import support for Origin project files
	xls	Import support for Microsoft office excel sheets
veusz	fits	Add FITS format via dev-python/pyfits

sec-policy

Package	Flag	Description
selinux-base-policy	open_perms	Enable the open permissions for file object classes (SELinux policy capability).
	peer_perms	Enable the labeled networking peer permissions (SELinux policy capability).
	ubac	Enable User Based Access Control (UBAC) in the SELinux policy

sys-apps

Package	Flag	Description
accountsservice	introspection	Use dev-libs/gobject-introspection for introspection
acl	nfs	add support for NFS acls
baselayout-prefix	prefix-chaining	install in a chained Prefix environment
busybox	make-symlinks	Create all the appropriate symlinks in /bin and /sbin.
	mdev	Create the appropriate symlink in /sbin and install mdev.conf and support files
	nfs	Support mounting nfs shares
dmtcp	fast	Enable experimental performance options such as mmap allocator.
dmtcp	trace	Enable ptrace support (only valid with debug enabled).
dstat	wifi	Enable wireless network functions
elfix	xtpax	Enable XT_PAX and prefer it to PT_PAX.
flashrom	atahpt	Highpoint (HPT) ATA/RAID controller support
	bitbang_spi	Bitbanging SPI infrastructure
	buspirate_spi	Enable Bus Pirate SPI programmer
	dediprog	Dediprog SF100 support
	drkaiser	Enable Dr. Kaiser programmer
	dummy	Enable dummy tracing
	ft2232_spi	Enable ftdi programmer, flashing through FTDI/SPI USB interface
	gfxnvidia	Enable NVIDIA programmer
	internal	Enable internal/onboard support
	nic3com	Enable 3Com NIC programmer
	nicintel	Support for Intel NICs
	nicintel_spi	Support for SPI on Intel NICs
	nicnatsemi	Support for National Semiconductor NICs
	nicrealtek	Support for Realtek NICs
	ogp_spi	Enable support for OGP (Open Graphics Project) SPI flashing
	rayer_spi	RayeR SPIPGM hardware support
	satamv	Enable programmer for Marvell SATA controllers
	satasii	Enable programmer for SiI SATA controllers
	serprog	Enable Serial Flasher programmer
	wiki	Enable wiki informations, like supported devices etc.
gnome-disk-utility	fat	Include FAT16/FAT32 support (sys-fs/dosfstools)
	nautilus	Enable gnome-base/nautilus extension.
	remote-access	Enable access to remote udisks daemons.
hwdata-gentoo	binary-drivers	Adds support for ATI/NVIDIA binary drivers
hwloc	numa	Add support for numa memory allocation
hwloc	pci	Enable PCI device discovery using libpci
ipmitool	openipmi	Use the system OpenIPMI implementation.
iproute2	iptables	include support for iptables filtering
irqbalance	numa	Support balancing IRQs across NUMA nodes
kexec-tools	lzma	Enables support for LZMA compressed kernel images
kexec-tools	xen	Enable extended xen support
kmod	compat	Install module-init-tools compatible symlinks.
kmod	tools	Install module loading/unloading tools.
lm_sensors	sensord	Enable sensord - a daemon that can be used to periodically log sensor readings from hardware health-monitoring chips
memtest86	serial	Compile with serial console support
memtest86+	floppy	Install a script to create floppy disks containing memtest86+ binaries.
memtest86+	serial	Compile with serial console support
moreutils	perl	Install scripts written in Perl
net-tools	old-output	use old ifconfig output style (useful for when new output breaks scripts)
pacman	gpg	Support verifying packages signed with GPG using app-crypt/gpgme
paludis	pbins	Enable binary package support. Adds dependency upon app-arch/libarchive
	pink	Use a less boring colourscheme than the default
	portage	Enable experimental support for Portage configuration formats
	prebuilt-documentation	Use pre-built documentation
	python-bindings	Enable Python bindings. Requires a lot of RAM to build (~700Mbytes per job) and adds a dependency upon dev-libs/boost
	ruby-bindings	Enable Ruby bindings.
	search-index	Enable cave search --index. Requires sqlite.
	visibility	Enable visibility support (g++ >=4.1)
pciutils	compress-db	Compress pci.ids database by default
	network-cron	Monthly cronjob the update-pciids script
	zlib	Support compressed pci.ids database
pcmciautils	staticsocket	Add support for static sockets
pcsc-lite	libusb	Use dev-libs/libusb detection to hotplug new smartcard readers. This flag should only be enabled if you're running a non-Linux kernel or you don't want to use sys-fs/udev.
	udev	Use sys-fs/udev rules to handle devices' permissions and hotplug support. Unless you know what you're doing do not disable this flag on Linux kernels. This is provided as an option for completeness.
	usb	Use dev-libs/libusb detection to hotplug new smartcard readers. This flag only makes sense on non-Linux systems, as on Linux, sys-fs/udev is used instead.
pcsc-tools	network-cron	Monthly cronjob the update-smartcard_list script
policycoreutils	audit	Enable support for sys-process/audit and use the audit_* functions (like audit_getuid instead of getuid())
portage	epydoc	Build html API documentation with epydoc.
	ipc	Use inter-process communication between portage and running ebuilds.
	less	Pull in sys-apps/less as default pager for etc-update.
	python2	Use python2 as Python interpreter.
	python3	Use python3 as Python interpreter.
pyrenamer	music	Enable support for renaming music
qingy	opensslcrypt	Encrypt communications between qingy and its GUI using dev-libs/openssl
razercfg	pm-utils	Installs the pm-utils hooks for suspend/resume and requires sys-power/pm-utils
razercfg	qt4	Installs a qt UI. Requires dev-python/pygtk
s390-tools	fuse	build cmsfs-fuse to read files stored on a z/VM CMS disk
s390-tools	zfcpdump	build the kernel disk dumping utility
shadow	audit	Enable support for sys-process/audit
smartmontools	minimal	Do not install the monitoring daemon and associated scripts.
superiotool	pci	Support for PCI-attached "Super I/Os" (e.g. in VIA VT82686A/B).
systemd	audit	Enable support for sys-process/audit
	cryptsetup	Use libcryptsetup
	plymouth	Enable support for sys-boot/plymouth
tcp-wrappers	netgroups	Support matching NIS (host) netgroup names via the @netgroup syntax (if you don't know what this means, you most likely need want it)
timer_entropyd	debug	Enable printf debugging and logging to the syslog at DEBUG level
tuxonice-userui	fbsplash	Add support for framebuffer splash
ucspi-ssl	tls	Add TLS support (see also http://www.suspectclass.com/~sgifford/ucspi-tls/)
usbutils	network-cron	Monthly cronjob the update-usbids script
usermode-utilities	fuse	Build tools (currently umlmount) needing fuse
util-linux	cramfs	build mkfs/fsck helpers for cramfs filesystems
	ddate	build ddate helper (Discordian dates)
	loop-aes	include support for Loop AES encryption
	perl	install the chkdupexe helper script
v86d	x86emu	Use x86emu for Video BIOS calls
watchdog	nfs	enable support for checking nfs mounts
xinetd	rpc	support RPC services

sys-auth

Package	Flag	Description
consolekit	policykit	Use the PolicyKit framework (sys-auth/polkit) to get authorization for suspend/shutdown.
munge	gcrypt	Use libgcrypt instead of openssl
pam_mktemp	prevent-removal	If supported, set EXT2_APPEND_FL on /tmp/.private to prevent temporary directories from being removed
pam_mysql	openssl	Use OpenSSL for md5 and sha1 support
pam_pkcs11	nss	Use Mozilla NSS (dev-libs/nss) as provider for PKCS#11 access, rather than using OpenSSL with a custom implementation of the PKC#11 protocol.
pam_pkcs11	pcsc-lite	Build the card_eventmanager binary used to detect card removal and lock the sessions. This needs sys-apps/pcsc-lite.
pambase	consolekit	Enable pam_ck_connector module on local system logins. This allows for console logins to make use of ConsoleKit authorization.
	cracklib	Enable pam_cracklib module on system authentication stack. This produces warnings when changing password to something easily crackable. It requires the same USE flag to be enabled on sys-libs/pam or system login might be impossible.
	debug	Enable debug information logging on syslog(3) for all the modules supporting this in the system authentication and system login stacks.
	gnome-keyring	Enable pam_gnome_keyring module on system login stack. This enables proper Gnome Keyring access to logins, whether they are done with the login shell, a Desktop Manager or a remote login systems such as SSH.
	minimal	Disables the standard PAM modules that provide extra information to users on login; this includes pam_tally (and pam_tally2 for Linux PAM 1.1 and later), pam_lastlog, pam_motd and other similar modules. This might not be a good idea on a multi-user system but could reduce slightly the overhead on single-user non-networked systems.
	mktemp	Enable pam_mktemp module on system auth stack for session handling. This module creates a private temporary directory for the user, and sets TMP and TMPDIR accordingly.
	pam_krb5	Enable pam_krb5 module on system auth stack, as an alternative to pam_unix. If Kerberos authentication succeed, only pam_unix will be ignore, and all the other modules will proceed as usual, including Gnome Keyring and other session modules. It requires sys-libs/pam as PAM implementation.
	pam_ssh	Enable pam_ssh module on system auth stack for authentication and session handling. This module will accept as password the passphrase of a private SSH key (one of ~/.ssh/id_rsa, ~/.ssh/id_dsa or ~/.ssh/identity), and will spawn an ssh-agent instance to cache the open key.
	passwdqc	Enable pam_passwdqc module on system auth stack for password quality validation. This is an alternative to pam_cracklib producing warnings, rejecting or providing example passwords when changing your system password. It is used by default by OpenWall GNU/*/Linux and by FreeBSD.
	sha512	Switch Linux-PAM's pam_unix module to use sha512 for passwords hashes rather than MD5. This option requires >=sys-libs/pam-1.0.1 built against >=sys-libs/glibc-2.7, if it's built against an earlier version, it will silently be ignored, and MD5 hashes will be used. All the passwords changed after this USE flag is enabled will be saved to the shadow file hashed using SHA512 function. The password previously saved will be left untouched. Please note that while SHA512-hashed passwords will still be recognised if the USE flag is removed, the shadow file will not be compatible with systems using an earlier glibc version.
polkit	introspection	Use dev-libs/gobject-introspection for introspection
polkit	systemd	Use sys-apps/systemd instead of sys-auth/consolekit for session tracking
sssd	glib	Use dev-libs/glib as UTF-8 string library
	libunistring	Use dev-libs/libunistring as UTF-8 string library
	locator	Install sssd's Kerberos plugin
	logrotate	Install logrotate.d file
	netlink	Add support for netlink protocol via dev-libs/libnl

sys-block

Package	Flag	Description
gparted	btrfs	Include Btrfs support (sys-fs/btrfs-progs)
	dmraid	Support for dmraid devices, also known as ATA-RAID, or Fake RAID.
	fat	Include FAT16/FAT32 support (sys-fs/dosfstools)
	gtk	Enable .desktop support for gtk+ based desktops.
	hfs	Include HFS support (sys-fs/hfsutils)
	jfs	Include JFS support (sys-fs/jfsutils)
	mdadm	Support for Linux software RAID.
	ntfs	Include NTFS support (sys-fs/ntfsprogs)
	reiser4	Include ReiserFS4 support (sys-fs/reiser4progs)
	reiserfs	Include ReiserFS support (sys-fs/reiserfsprogs)
	xfs	Include XFS support (sys-fs/xfsprogs, sys-fs/xfsdump)
open-iscsi	modules	Build the open-iscsi kernel modules
open-iscsi	utils	Build the open-iscsi utilities
parted	debug	Enable debugging as encouraged by upstream: [The default configuration] includes --enable-debug (by default), which contains many assertions. Obviously, these "waste" space, but in the past, they have caught potentially dangerous bugs before they would have done damage, so we think it's worth it. Also, it means we get more bug reports ;)
parted	device-mapper	Enable sys-fs/device-mapper support in parted
partimage	nologin	Do not include login support when connecting partimaged
tgt	fcoe	Add support for FCoE protocol
	fcp	Add support for new FC protocol
	ibmvio	Add support for IBM Virtual I/O

sys-boot

Package	Flag	Description
grub	device-mapper	Enable support for sys-fs/device-mapper
grub	efiemu	Build and install the efiemu runtimes
lilo	device-mapper	Enable support for sys-fs/device-mapper
	minimal	Do not install the dolilo helper script
	pxeserial	Avoid character echo on PXE serial console
plymouth	gdm	Enables smooth transition to GDM
	libkms	Provides abstraction to the DRM drivers (intel, nouveau and vmwgfx at this moment)
	openrc	Installs plugin for OpenRC
	pango	Adds support for printing text on splash screen and text prompts, e.g. for password

sys-cluster

Package	Flag	Description
ceph	fuse	Build fuse client
	libatomic	Use libatomic instead of builtin atomic operations
	radosgw	Add radosgw support
charm	cmkopt	Enable CMK optimisation
charm	tcp	Use TCP (instead of UPD) for socket communication
cluster-glue	large-cluster	Extend messages length limits for resource heavy clusters
cluster-glue	libnet	Force use of net-libs/libnet
corosync	infiniband	Enable Infiniband RDMA transport support
drbd	heartbeat	Enable Heartbeat integration
	pacemaker	Enable Pacemaker integration
	xen	Enable Xen integration
gearmand	drizzle	Support dev-db/libdrizzle for the queue storage. This also adds support for MySQL storage.
	memcache	Support memcache daemon (via dev-libs/libmemcached) for the queue storage.
	tokyocabinet	Support dev-db/tokyocabinet for the queue storage.
glusterfs	extras	Install extra helper scripts
	fuse	Add FUSE mount helper
	infiniband	Add support for Infiniband ibverbs transport. Libraries can be found in science overlay
lam-mpi	pbs	Add support for the Portable Batch System (PBS)
	romio	Enable romio, a high-performance portable MPI-IO implementation
	xmpi	Build support for the external XMPI debugging GUI
maui	pbs	Enable pbs integration
maui	slurm	Enable slurm integration
moosefs	cgi	Install CGI server and scripts.
moosefs	fuse	Install the mfsmount utility.
mpi-dotnet	doc	Install tutorials for C# and IronPython (requires a Word document reader)
mpi-dotnet	examples	Install small, illustrative projects using MPI.Net
mpich2	mpi-threads	Enable MPI_THREAD_MULTIPLE
mpich2	romio	Enable romio, a high-performance portable MPI-IO implementation
mvapich2	large-cluster	Automatically generated description for large-cluster
	medium-cluster	Automatically generated description for medium-cluster
	romio	Automatically generated description for romio
ocfs	aio	Add aio support
openmpi	heterogeneous	Enable features required for heterogeneous platform support
	knem	Add High-Performance intranode communication
	mpi-threads	Enable MPI_THREAD_MULTIPLE
	numa	Enable numa memory allocation support
	open-mx	Add support for Myrinet Express over Ethernet>
	pbs	Add support for the Portable Batch System (PBS)
	psm	Add support for Qlogic psm driver for IB
	romio	Build the ROMIO MPI-IO component
	sctp	Enable SCTP support
	slurm	Add support for SLURM
	vt	Enable bundled VampirTrace support
pacemaker	ais	Enable sys-cluster/openais support.
	cman	Enable sys-cluster/cman support.
	heartbeat	Enable sys-cluster/heartbeat support.
	smtp	Enable SMTP support via net-libs/libsmtp
pacemaker-gui	gtk	Enable the GTK+ based GUI client.
pacemaker-gui	heartbeat	Enable support for heartbeat based sys-cluster/pacemaker.
resource-agents	libnet	Force use of net-libs/libnet
slurm	maui	Enable maui scheduler support
	munge	Enable authentication via munge
	torque	Enable perl scripts that emulates pbs (qstat, qsub etc.)
torque	cpusets	Enable pbs_mom to utilize linux cpusets if available
	drmaa	Enable the Distributed Resource Management Application API
	munge	Enable authentication via munge
	server	Enable compilation of pbs_server and pbs_sched

sys-devel

Package	Flag	Description
binutils	multislot	Allow for multiple versions of binutils to be emerged at once for same CTARGET
binutils	multitarget	Adds support to binutils for cross compiling (does not work with gas)
binutils-apple	lto	Add support for Link-Time Optimization with LLVM
binutils-hppa64	multislot	Allow for multiple versions of binutils to be emerged at once for same CTARGET
binutils-hppa64	multitarget	Adds support to binutils for cross compiling (does not work with gas)
clang	multitarget	Build all host targets (default: host only)
	static-analyzer	Install the Clang static analyzer
	system-cxx-headers	By default, clang++ searchs for C++ headers in a series of hardcoded paths. Enabling this flag will force it to use the active gcc profile ones
distcc	crossdev	Enable support for sys-devel/crossdev
distcc	gssapi	Enable support for net-libs/libgssglue
gcc	d	Enable support for the D programming language
	fixed-point	Enable fixed-point arithmetic support for MIPS targets in gcc (Warning: significantly increases compile time!)
	go	Build the GCC Go language frontend.
	graphite	Add support for the framework for loop optimizations based on a polyhedral intermediate representation
	gtk	Useful only when building GCJ, this enables Abstract Window Toolkit (AWT) peer support on top of GTK+
	ip28	Enable building a compiler capable of building a kernel for SGI Indigo2 Impact R10000 (IP28)
	ip32r10k	Enable building a compiler capable of building an experimental kernel for SGI O2 w/ R1x000 CPUs (IP32)
	libffi	Build the portable foreign function interface library
	libssp	Build SSP support into a dedicated library rather than use the code in the C library (DO NOT ENABLE THIS IF YOU DON'T KNOW WHAT IT DOES)
	lto	Add support for link-time optimizations (unsupported, use at your own risk).
	mudflap	Add support for mudflap, a pointer use checking library
	multislot	Allow for SLOTs to include minor version (3.3.4 instead of just 3.3)
	n32	Enable n32 ABI support on mips
	n64	Enable n64 ABI support on mips
	nopie	Disable PIE support (NOT FOR GENERAL USE)
	nossp	Disable SSP support (NOT FOR GENERAL USE)
	objc	Build support for the Objective C code language
	objc++	Build support for the Objective C++ language
	objc-gc	Build support for the Objective C code language Garbage Collector
gcc-apple	multislot	Allow for SLOTs to include minor version (3.3.4 instead of just 3.3)
	objc	Build support for the Objective C code language
	objc++	Build support for the Objective C++ language
gdb	client	Install the main "gdb" program (most people want this)
	multitarget	Support all known targets in one gdb binary
	python	Enable support for the new internal scripting language, as well as extended pretty printers
	server	Install the "gdbserver" program (useful for embedded/remote targets)
gettext	git	When running `autopoint`, use git to store the internal development files; this requires git at runtime, but will be faster/smaller than raw archives
kgcc64	multislot	Allow for SLOTs to include minor version (eg. 3.3.4 instead of just 3.3)
libperl	ithreads	Enable Perl threads, has some compatibility problems
llvm	gold	Build the gold linker plugin
	llvm-gcc	Build LLVM with sys-devel/llvm-gcc
	multitarget	Build all host targets (default: host only)
	udis86	Enable support for dev-libs/udis86 disassembler library
sparse	gtk	Build the test-inspect utility (requires x11-libs/gtk+ version 2)
sparse	xml	Build the c2xml utility (requires dev-libs/libxml2).

sys-freebsd

Package	Flag	Description
boot0	tftp	Enable PXE/TFTP boot support.
boot0	zfs	Enable booting on ZFS filesystems.
freebsd-lib	hesiod	Enable support for net-dns/hesiod
	netware	Build libraries and tools to work with NetWare protocols (IPX and NCP).
	zfs	Enable ZFS support.
freebsd-rescue	netware	Build tools to work with NetWare protocols (IPX and NCP).
freebsd-rescue	zfs	Enable ZFS support.
freebsd-sbin	ipfilter	Build tools to administer the ipfilter firewall.
	netware	Build libraries and tools to work with NetWare protocols (IPX and NCP).
	pf	Build tools to administer the PF firewall.
freebsd-share	isdn	Enable ISDN support
freebsd-ubin	ar	Build FreeBSD's ar and ranlib replacements based on libarchive. The toolchain will still use binutils' version but you can play with it. They have been renamed to freebsd-ar and freebsd-ranlib not to collide with binutils.
	audit	Build auditing tools.
	netware	Build libraries and tools to work with NetWare protocols (IPX and NCP).
	zfs	Enable ZFS support (for fstat actually).
freebsd-usbin	audit	Build auditing tools.
	floppy	Enable floppy disk utilities (fdcontrol, fdformat, fdread, fdwrite).
	isdn	Enable ISDN support.
	netware	Build libraries and tools to work with NetWare protocols (IPX and NCP).

sys-fs

Package	Flag	Description
aufs2	debug	Enable additional debugging support
	fuse	Enable fuse support
	hfs	Enable hfs support
	inotify	Enable inotify support
	kernel-patch	Patch the current kernel for aufs2 support
	nfs	Enable support for nfs export
	pax_kernel	Apply patch needed for pax enabled kernels
	ramfs	Enable initramfs/rootfs support
aufs3	debug	Enable additional debugging support
	fuse	Enable fuse support
	hfs	Enable hfs support
	inotify	Enable inotify support
	kernel-patch	Patch the current kernel for aufs2 support
	nfs	Enable support for nfs export
	pax_kernel	Apply patch needed for pax enabled kernels
	ramfs	Enable initramfs/rootfs support
btrfs-progs	debug-utils	Build additional utils for debugging
cryptsetup	dynamic	Build cryptsetup dynamically
dmraid	dietlibc	Compile against dev-libs/dietlibc
	intel_led	Enable Intel LED support
	klibc	Compile against dev-libs/klibc
	led	Enable LED support
	mini	Create a minimal binary suitable for early boot environments
ecryptfs-utils	gpg	Enable app-crypt/gnupg key module
	openssl	Enable dev-libs/openssl key module
	pkcs11	Enable PKCS#11 (Smartcards) key module
	tpm	Enable support for Trusted Platform Module (TPM) using app-crypt/trousers
lessfs	filelog	Enable the ability to log to a file instead of syslog
lessfs	memtrace	Enable leefs to create a report regarding the memory allocation. This feature should be used for debugging purposes to avoid performance degradation
loop-aes	aes-ni	Enable support for Intel's AES instruction set
	extra-ciphers	Enable extra ciphers
	keyscrub	Protects the encryption key in memory but takes more cpu resources
	padlock	Use VIA padlock instructions, detected at run time, code still works on non-padlock processors
lvm2	clvm	Allow users to build clustered lvm2
	cman	Cman support for clustered lvm
	lvm1	Allow users to build lvm2 with lvm1 support
	nolvmstatic	Allow users to build lvm2 dynamically
ntfs3g	crypt	Add support for encrypted NTFS drives/partitions.
	external-fuse	Use external FUSE library instead of internal one. Must be disabled for unprivileged mounting to work.
	extras	Enable extra ntfsprogs utilities.
	ntfsprogs	Include internal version of ntfsprogs. This will block sys-fs/ntfsprogs.
	udev	Install udev rule to make udisks use ntfs-3g instead of the kernel NTFS driver.
ntfsprogs	fuse	Build a FUSE module
ocfs2-tools	external	Enable external locking
owfs	ftpd	Enable building the OWFS FTP server (owftpd)
	fuse	Enable building the FUSE-based OWFS client (owfs)
	httpd	Enable building the OWFS web server (owhttpd)
	parport	Enable support for the DS1410E parallel port adapter
	server	Enable building the OWFS server (owserver)
pysize	psyco	Adds psyco support
quota	netlink	Compile daemon receiving quota messages via netlink
quota	rpc	Enable quota interaction via RPC
s3ql	contrib	Install additional contributed scripts
udev	acl	apply ACLs for users with local forground sessions
	action_modeswitch	switch Mobile Action cables into serial mode
	devfs-compat	Install rules for devfs compatible device names
	edd	create /dev/disk/by-id/edd-* links for BIOS EDD data
	extras	Compile udev-extras requiring external dependencies
	floppy	create historical floppy kernel device nodes (/dev/fd0h1440, ...)
	gudev	enable libudev gobject interface
	hwdb	read vendor/device string database and add it to udev database
	introspection	Use dev-libs/gobject-introspection for introspection
	keymap	map custom hardware's multimedia keys
	old-hd-rules	Install rules for /dev/hd* devices, removed upstream at udev-148
	rule_generator	enable persistent network and optical device rule generator
udisks	remote-access	Control whether connections from other clients over LAN are allowed

sys-infiniband

Package	Flag	Description
openib	dapl	Automatically generated description for dapl
	diags	Automatically generated description for diags
	ehca	Automatically generated description for ehca
	ipath	Automatically generated description for ipath
	mlx4	Automatically generated description for mlx4
	mthca	Automatically generated description for mthca
	nes	Automatically generated description for nes
	opensm	Automatically generated description for opensm
	srp	Add support for srp targets
openib-files	ehca	Automatically generated description for ehca
	ipath	Automatically generated description for ipath
	iser	Automatically generated description for iser
	mlx4	Automatically generated description for mlx4
	rds	Automatically generated description for rds
	srp	Automatically generated description for srp
	vnic	Automatically generated description for vnic

sys-kernel

Package	Flag	Description
ck-sources	deblob	Remove binary blobs from kernel sources to provide libre license compliance.
dracut	debug	Module installing additional tools like strace, file editor, ssh and more
gentoo-sources	deblob	Remove binary blobs from kernel sources to provide libre license compliance.
hardened-sources	deblob	Remove binary blobs from kernel sources to provide libre license compliance.
linux-docs	html	Install HTML documentation
linux-firmware	savedconfig	Allows individual selection of firmware files
mips-sources	cobalt	Enables support for Cobalt Microserver hardware (Qube2/RaQ2)
	deblob	Remove binary blobs from kernel sources to provide libre license compliance.
	impactdebug	Enables use of the IP30 Impact Early Console Hack. FOR DEBUGGING ONLY!
	ip27	Enables support for SGI Origin (IP27)
	ip28	Enables support for SGI Indigo2 Impact R10000 (IP28)
	ip30	Enables support for SGI Octane (IP30, 'Speedracer')
	ip32r10k	Enables experimental support for IP32 R10K kernels (SGI O2, 'Moosehead')
	odysseydebug	Enables use of the IP30 Odyssey Early Console Hack. FOR DEBUGGING ONLY!
openvz-sources	deblob	Remove binary blobs from kernel sources to provide libre license compliance.
pf-sources	deblob	Remove binary blobs from kernel sources to provide libre license compliance.
pf-sources	experimental	Apply patches that are considered experimental. For more information, check out the ChangeLog or the ebuild that interests you.
rt-sources	deblob	Remove binary blobs from kernel sources to provide libre license compliance.
sparc-sources	ultra1	If you have a SUN Ultra 1 with a HME interface
tuxonice-sources	deblob	Remove binary blobs from kernel sources to provide libre license compliance.
vanilla-sources	deblob	Remove binary blobs from kernel sources to provide libre license compliance.
vserver-sources	deblob	Remove binary blobs from kernel sources to provide libre license compliance.
xen-sources	deblob	Remove binary blobs from kernel sources to provide libre license compliance.
zen-sources	bfq	Make the BFQ IO Scheduler available by applying upstream patches
	deblob	Remove binary blobs from kernel sources to provide libre license compliance.
	minimal	Clone git tree with --depth 1 to reduce amount of data to download. Use with caution
	tuxonice	Apply TuxOnIce kernel patches advanced hibernation support

sys-libs

Package	Flag	Description
gdbm	berkdb	enable compatibility layer for UNIX-like dbm and ndbm interfaces
gdbm	exporter	enable gdbmexport binary for exporting data from gdbm-1.8 databases into gdbm-1.9
glibc	glibc-omitfp	Configure with --enable-omitfp which lets the build system determine when it is safe to use -fomit-frame-pointer
glibc	linuxthreads	Build linuxthreads support (only for kernels older than linux-2.6)
gwenhywfar	fox	Use x11-libs/fox graphical toolkit
libosinfo	introspection	Use dev-libs/gobject-introspection for introspection
libosinfo	vala	Enable bindings for dev-lang/vala
ncurses	ada	Add bindings for the ADA programming language
ncurses	trace	Enable test trace() support in ncurses calls
pam	audit	Enable support for sys-process/audit
	berkdb	Build the pam_userdb module, that allows to authenticate users against a Berkeley DB file. Please note that enabling this USE flag will create a PAM module that links to the Berkeley DB (as provided by sys-libs/db) installed in /usr/lib and will thus not work for boot-critical services authentication.
	cracklib	Build the pam_cracklib module, that allows to verify the chosen passwords' strength through the use of sys-libs/cracklib. Please note that simply enabling the USE flag on this package will not make use of pam_cracklib by default, you should also enable it in sys-auth/pambase as well as update your configuration files.
talloc	compat	Enable extra compatibility stuff
talloc	swig	Install interface definitions for dev-lang/swig
tdb	tdbtest	Install tdbtest app
tdb	tools	Install extra tools
uclibc	pregen	Use pregenerated locales
	savedconfig	Adds support for user defined configs
	ssp	Force the use of ssp to be built into a hardened uclibc setup
	uclibc-compat	Build uclibc with backwards compatible options
	userlocales	Build only the locales specified in /etc/locales.build
	wordexp	Add support for word expansion (wordexp.h)
zlib	minizip	include the minizip library for quick and dirty zip extraction

sys-power

Package	Flag	Description
cpufreqd	nforce2	Enable support for nforce2 voltage settings plug-in
	nvidia	Enable nvidia overclocking (media-video/nvclock) plug-in
	pmu	Enable Power Management Unit plug-in
nvclock	gtk	Install the GTK+ based graphical interface
nvclock	nvcontrol	Add NVCONTROL support for OpenGL options
phctool	sudo	Enable support for sudo to run gui from non-root user
pm-utils	ntp	Install support for net-misc/ntp
powerman	genders	Add support for selecting power control targets using genders (-g option)
	h8power	Add support for h8 based power controllers
	httppower	Add support for HTTP based power controllers
	snmppower	Add support for SNMP based power controllers
powermgmt-base	pm-utils	Adds support for on_ac_power through sys-power/pm-utils
suspend	crypt	Allows suspend and resume from encrypted disk
suspend	fbsplash	Add support for framebuffer splash
upower	introspection	Use dev-libs/gobject-introspection for introspection

sys-process

Package	Flag	Description
cronie	inotify	Enable inotify filesystem monitoring support.
fcron	debug	Enable debug code and output. Since version 3.0.5 this will no longer force foreground execution, and fcron will be able to run as a service properly.
fcron	pam	Enable PAM support for fcron. This means that fcron will pass through the "fcron" stack before executing the jobs, and fcrontab will use the "fcrontab" stack to authenticate the user before editing its crontab file.
htop	openvz	Enable openvz support
htop	vserver	Enable vserver support
lsof	rpc	support looking up RPC service info
procps	ncurses	Build programs that use ncurses: top, slabtop, watch

virtual

Package	Flag	Description
ffmpeg	vaapi	Enables VAAPI (Video Acceleration API) for hardware decoding
ffmpeg	vdpau	Enables VDPAU decoders (requires nVidia video cards to offload CPU processing to video card
mpi	romio	Enable romio, a high-performance portable MPI-IO
mysql	embedded	Build embedded server (libmysqld)

www-apache

Package	Flag	Description
mod_extract_forwarded	mod_proxy	Enable support for Apache's internal proxy
mod_nss	ecc	enable Elliptical Curve Cyptography
mod_security	curl	Build the ModSecurity Audit Log Collector (mlogc) that depends on net-misc/curl.
	geoip	Configure ModSecurity to query the GeoIP database from MaxMind, provided by dev-libs/geoip. This flag only controls the default configuration, as the GeoIP query code is part of ModSecurity's source code.
	perl	Add a dependency upon Perl and install the script to update the Core Rule Set. Please note that this script will use the original Core Rule Set, and it's currently mostly untested.
	vanilla	Provide the original ModSecurity Core Rule Set without Gentoo-specific relaxation. When this flag is enabled, we install the unadulterated Core Rule Set. Warning! The original Core Rule Set is draconic and most likely will break your web applications, including Rails-based web applications and Bugzilla.
mod_suphp	checkpath	Check if script resides in DOCUMENT_ROOT
	mode-force	Run scripts with UID/GID specified in Apache configuration
	mode-owner	Run scripts with owner UID/GID
	mode-paranoid	Run scripts with owner UID/GID but also check if they match the UID/GID specified in the Apache configuration
mod_vhs	suphp	Enable www-apache/mod_suphp support
pwauth	domain-aware	Ignore leading domain names in username (Windows compat)
	faillog	Log failed login attempts
	ignore-case	Ignore string case in username (mostly Windows compat)

www-apps

Package	Flag	Description
389-dsgw	adminserver	Install DSGW with Admin Server
ampache	transcode	Install optional dependencies for transcoding support
bugzilla	extras	Optional Perl modules
bugzilla	modperl	Enable www-apache/mod_perl support
cgit	highlight	Enable source code highlighting
egroupware	gallery	Install gallery2 port for eGW
	icalsrv	Install iCal Server (eGroupware-iCalSrv)
	jpgraph	Add dev-php5/jpgraph support
	mydms	Install eGroupware-MyDMS
gallery	netpbm	Add media-libs/netpbm support
	unzip	Add app-arch/unzip support for the archive upload module
	zip	Add app-arch/zip for the zip download module
horde-passwd	clearpasswd	Enables cleartext password storage in the vpopmail files
ikiwiki	extras	Installs additional modules used by ikiwiki plugins
lxr	freetext	Adds support for freetext search using swish-e
mediawiki	math	Ads math rendering support
otrs	mod_perl	Provide all dependencies for use of mod_perl instead of cgi
postfixadmin	extras	Install contributed scripts and plugins
	tests	Install model unit tests
	vacation	Install vacation.pl script and dependencies
redmine	darcs	Enable support for dev-vcs/darcs
	git	Enable support for dev-vcs/git
	mercurial	Enable support for dev-vcs/mercurial
	openid	Enable support for OpenID
	passenger	Enable support for www-apache/passenger
rt	lighttpd	Add www-servers/lighttpd support
trac	i18n	Enable support for i18n with dev-python/Babel
tt-rss	daemon	Install additional init scripts for automated RSS updates
venus	django	Support for django template style to config files
	genshi	Support for genshi style to config files
	redland	Enable support for Redland RDF
viewvc	cvsgraph	Add dev-vcs/cvsgraph support to show graphical views of revisions and branches
	mod_python	Add www-apache/mod_python support
	mod_wsgi	Add www-apache/mod_wsgi support
	pygments	Add dev-python/pygments support for syntax highlighting

www-client

Package	Flag	Description
elinks	bittorrent	Enable support for the BitTorrent protocol
	finger	Enable support for the finger protocol
	gopher	Enable support for the gopher protocol
	mouse	Make elinks to grab all mouse events
epiphany	introspection	Use dev-libs/gobject-introspection for introspection
epiphany	nss	Import passwords from older gecko based www-client/epiphany keyring.
firefox	bindist	Disable official Firefox branding (icons, name) which are not binary-redistributable according to upstream.
	crashreporter	Enable crashreporter for mozilla upstream, debugging symbols are not required for reporting crashes.
	custom-optimization	Fine-tune custom compiler optimizations, setting this is not recommended.
	ipc	Use inter-process communication between tabs and plugins. Allows for greater stability in case of plugin crashes
	pgo	Add support for profile-guided optimization using gcc-4.5, for faster binaries. This option will double the compile time.
	system-sqlite	Use the system-wide dev-db/sqlite installation with secure-delete enabled
	webm	Use system media-libs/libvpx for HTML5 WebM video support.
google-chrome	plugins	Add system plugins path to launcher
icecat	crashreporter	Enable crashreporter for mozilla upstream, debugging symbols are not required for reporting crashes.
	custom-optimization	Fine-tune custom compiler optimizations
	ipc	Use inter-process communication between tabs and plugins. Allows for greater stability in case of plugin crashes
	pgo	Add support for profile-guided optimization using gcc-4.5, for faster binaries. This option will double the compile time.
	system-sqlite	Use the system-wide dev-db/sqlite installation with secure-delete enabled
	webm	Use system libvpx media-libs/libvpx
leechcraft-poshuku	cleanweb	Build CleanWeb for ad blocking compatible with Firefox's AdBlock+.
	fatape	Build FatApe, GreaseMonkey userscripts support layer.
	filescheme	Build FileScheme for accessing local URLs.
	fua	Build FUA for faking user agents for different hosts.
	keywords	Build Keywords for adjusting search shortcuts.
	onlinebookmarks	Build OnlineBookmarks for syncing bookmarks with social bookmarking services like Read It Later.
	pogooglue	Build Pogooglue for searching for selected words in Google in two clicks
	wyfv	Build WYFV for replacing Flash-based video players on some sites.
luakit	helpers	Optional tools used by luakit
luakit	luajit	Use the lua just-in-time compiler dev-lang/luajit instead of dev-lang/lua, which should make luakit faster.
lynx	gnutls	Use gnutls library for HTTPS support (openssl is the default library for HTTPS support).
lynx	ssl	Enable HTTPS support.
midori	unique	Enable single instance support using dev-libs/libunique
opera	gtk	Set runtime dependencies to support GTK+/GNOME version 2 desktop integration
	gtk3	Set runtime dependencies to support GTK+/GNOME version 3 desktop integration
	kde	Set runtime dependencies to support KDE desktop integration
opera-next	gtk	Set runtime dependencies to support GTK+/GNOME version 2 desktop integration
	gtk3	Set runtime dependencies to support GTK+/GNOME version 3 desktop integration
	kde	Set runtime dependencies to support KDE desktop integration
seamonkey	chatzilla	Build Mozilla's IRC client (default on)
	composer	Build Mozilla's HTML editor component (default on)
	custom-optimization	Fine-tune custom compiler optimizations
	ipc	Use inter-process communication between tabs and plugins. Allows for greater stability in case of plugin crashes
	mailclient	Build Mozilla's Mail client (default on)
	methodjit	Enable JIT for JavaScript using MethodJIT for faster JS performance. Hardened users can disable this USE-flag to use MPROTECT on grsecurity kernels.
	roaming	Build roaming extension support (default on)
	system-sqlite	Use the system-wide dev-db/sqlite installation with secure-delete enabled
	webm	Use system media-libs/libvpx for HTML5 WebM video support.
uget	aria2	Enable support for net-misc/aria2 through xmlrpc. You'll find the plugin in the app's settings.
	gtk3	Use x11-libs/gtk+:3 instead of x11-libs/gtk+:2
	hide-temp-files	Make temporary files that are used while downloading hidden.
uzbl	browser	Install the uzbl-browser script
	experimental	Enable experimental branch
	gtk3	Use x11-libs/gtk+:3 instead of x11-libs/gtk+:2
	helpers	Optional tools used by uzbl scripts
	tabbed	Install the uzbl-tabbed script
w3m	lynxkeymap	If you prefer Lynx-like key binding

www-misc

Package	Flag	Description
vdradmin-am	vdr	Support for media-video/vdr. Disable this if the VDR you want to control runs at a remote machine.
xxv	themes	Enable more themes via x11-themes/xxv-skins

www-plugins

Package	Flag	Description
adobe-flash	32bit	For amd64-multilib, installs the 32-bit plugin
	64bit	For amd64-multilib, installs the native 64-bit plugin
	bindist	With USE="-bindist", applies a binary patch to the native 64-bit plugin for compatibility with glibc-2.13 (Bug #354073). Required due to the non-modification clause in Adobe's license.
	kde	Enables a KCM plugin for configuring flash player preferences (32-bit KDE4 only)
	vdpau	Enables VDPAU support to offload video processing (32-bit flash player only)
gnash	agg	Rendering based on the Anti-Grain Geometry Rendering Engine library
	cygnal	Enable building of the cygnal server
	openvg	Rendering based on the OpenVG graphics acceleration API
	sdl-sound	Enable SDL audio output for the standalone player
	ssh	Enable using SSH for network authentication in libnet
	ssl	Enable directly using OpenSSL in libnet (not needed for nsplugin ssl support)
	vaapi	Enables VAAPI (Video Acceleration API) for hardware decoding
google-talkplugin	system-libCg	Use system libCg instead of bundled one
lightspark	rtmp	Enable Real Time Messaging Protocol using librtmp
mozplugger	xembed	Build with xembed always enabled.

www-servers

Package	Flag	Description
apache	static	Link in apache2 modules statically rather then plugins
apache	suexec	Install suexec with apache
cherokee	admin	Install web based cherokee conf tool
	coverpage	Installs the default cherokee coverpage
	rrdtool	Enable rrdtool support
fnord	auth	Enable HTTP authentication support
lighttpd	libev	Enable fdevent handler
	memcache	Enable memcache support for mod_cml and mod_trigger_b4_dl
	rrdtool	Enable rrdtool support via mod_rrdtool
	uploadprogress	Apply experimental patch for upload progress module
	webdav	Enable webdav properties
nginx	aio	Enables file AIO support
	http	Enable HTTP core support
	http-cache	Enable HTTP cache support
	libatomic	Use libatomic instead of builtin atomic operations
	nginx_modules_http_addition	This module adds contents of other locations before and after the current location's content.
	nginx_modules_http_dav	This module adds the HTTP and WebDAV methods PUT, DELETE, MKCOL, COPY and MOVE.
	nginx_modules_http_flv	This module provides the ability to seek within FLV (Flash) files using time-based offsets.
	nginx_modules_http_gzip_static	Enables support for gzipping static content on disk
	nginx_modules_http_mp4	This module adds pseudo-streaming support for H.264/AAC in MP4 containers.
	nginx_modules_http_random_index	Pick a random directory index from a directory.
	nginx_modules_http_realip	This module allows to change the client's IP address to value from request header (e. g. X-Real-IP or X-Forwarded-For).
	nginx_modules_http_slowfs_cache	This module adds the ability to cache static files
	nginx_modules_http_stub_status	This module provides the ability to get some status from nginx
	nginx_modules_http_sub	Enable support for search and replace text in the nginx response
	nginx_modules_http_upload	Enable support for handling file uploads using multipart/form-data encoding
	nginx_modules_http_upload_progress	This module adds the ability to track POST upload progress via JSON API
	nginx_modules_mail_imap	Enables IMAP proxy support
	nginx_modules_mail_pop3	Enables POP3 proxy support
	nginx_modules_mail_smtp	Enables SMTP proxy support
	pcre-jit	Enable JIT for pcre
ocsigen	ocamlduce	Enables ocamlduce XML typechecking for generated web pages
pound	dynscaler	Enable dynamic rescaling of back-end priorities
pshs	magic	Enable automatic detection of Content-Type using libmagic (sys-apps/file)
	netlink	Use libnetlink (sys-apps/iproute2) to get network interface addresses
	upnp	Enable port forwarding using UPnP via net-libs/miniupnpc
resin	admin	Enable Resin admin webapp
varnish	tools	Build additional tools: varnishhist, varnishstat, varnishtop, varnishsizes

x11-apps

Package	Flag	Description
ardesia	cwiid	cwiid support: collection of Linux tools written in C for interfacing to the Nintendo Wiimote.
xdm	consolekit	Enable native sys-auth/consolekit support
xdpyinfo	dmx	Builds support for Distributed Multiheaded X x11-base/xorg-server
xinit	minimal	Control dependencies on legacy apps (xterm, twm, ...). Safe to enable if you use a modern desktop environment.
xsm	rsh	This allows the use of rsh (remote shell) and rcp (remote copy).

x11-base

Package	Flag	Description
xorg-server	dmx	Build the Distributed Multiheaded X server
	kdrive	Build the kdrive X servers
	tslib	Build with tslib support for touchscreen devices
	xnest	Build the Xnest server
	xorg	Build the Xorg X server (HIGHLY RECOMMENDED)
	xvfb	Build the Xvfb server

x11-drivers

Package	Flag	Description
ati-drivers	modules	Build the kernel modules
	opencl	Install OpenCL runtime libraries
	pax_kernel	Enable if the user plans to run the package under a pax enabled hardened kernel
	qt4	Install qt4 dependent optional tools (e.g Catalyst Control Panel)
xf86-video-geode	ztv	Enable building the V4L2 ZTV driver
xf86-video-intel	sna	Enable SandyBridge's New Acceleration (useful on all chipsets, not just SandyBridge)
xf86-video-qxl	xspice	Build the xspice driver

x11-libs

Package	Flag	Description
agg	gpc	Enable gpc polygon clipper library
cairo	cleartype	Add ClearType-style behavior for sub-pixel hinting. Patch taken from Arch Linux
	drm	Use Linux DRM for backend acceleration
	gallium	Use Mesa's Gallium backend for acceleration
	glib	Compile with GLib Object System support
	lcdfilter	Add FreeType LCD filtering, ClearType-style behavior for sub-pixel-hinting. Overrides cleartype USE flag. Patch taken from Ubuntu
	opengl	Use Mesa backend for acceleration
	openvg	Use OpenVG for backend acceleration
fltk	games	Builds and installs some extra games
gdk-pixbuf	introspection	Use dev-libs/gobject-introspection for introspection
goocanvas	introspection	Use dev-libs/gobject-introspection for introspection
gtk+	colord	Use x11-misc/colord for color management in printing
	introspection	Use dev-libs/gobject-introspection for introspection
	packagekit	Enable support for the distro-neutral package manager GUI app-admin/packagekit in application chooser
gtk+extra	introspection	Use dev-libs/gobject-introspection for introspection
gtkdatabox	glade	Build with libglade and glade-3 supports, which includes a glade's module for GtkDataBox widget
gtkmathview	mathml	Install additional fonts for proper mathml support.
gtkmathview	t1lib	Enable media-libs/t1lib support
gtksourceview	glade	Install a glade catalog file
gtksourceview	introspection	Use dev-libs/gobject-introspection for introspection
libSM	uuid	Use UUID for session identification instead of IP address and system time.
libaosd	pango	Enable the textual helpers (requires pangocairo).
libaosd	tools	Install the aosd_cat tool (requires glib-2.0).
libcryptui	introspection	Use dev-libs/gobject-introspection for introspection
libdesktop-agnostic	gconf	Enable GConf as configuration backend
	glade	Install the Glade catalog for the desktop-agnotstic GTK widgets.
	introspection	Use dev-libs/gobject-introspection for introspection
libdrm	libkms	Enable building of libkms, a library for applications to interface with KMS
libfm	demo	Build demo
libmatchbox	pango	Enable x11-libs/pango support
libmatchbox	xsettings	Enable the use of xsettings for settings management
libnotify	introspection	Use dev-libs/gobject-introspection for introspection
libnotify	symlink	Create symlink from libnotify-notify-send to notify-send
libqxt	berkdb	Build the QxtBerkeley module
	sql	Build the QxtSql module
	web	Build the QxtWeb module
	zeroconf	Build the QxtZeroconf module
libwnck	introspection	Use dev-libs/gobject-introspection for introspection
libxklavier	introspection	Use dev-libs/gobject-introspection for introspection
mx	glade	Build the dev-util/glade catalog files
mx	introspection	Use dev-libs/gobject-introspection for introspection
pango	introspection	Use dev-libs/gobject-introspection for introspection
qt-assistant	c++0x	Build Qt using the C++11 standard
	compat	Build the extra compatibility package required by a few packages. More information at http://labs.qt.nokia.com/2010/06/22/qt-assistant-compat-version-available-as-extra-source-package/
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	glib	Enable dev-libs/glib eventloop support
	qpa	Build a window system agnostic implementation of Qt
	qt3support	Enable the Qt3Support libraries for Qt4. Note that this does not mean you can compile pure Qt3 programs with Qt4.
	trace	Build the qttracereplay utility which is required to play drawings recorded with the trace graphicssystem engine
	webkit	Build the WebView QML element
qt-core	c++0x	Build Qt using the C++11 standard
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	glib	Enable dev-libs/glib eventloop support
	jit	Enables JIT for Javascript usage inside Qt
	optimized-qmake	Enable qmake optimization
	private-headers	Install Qt declarative private headers required by Qt-creator QmlDesigner and QmlInspector plugins"
	qpa	Build a window system agnostic implementation of Qt
	qt3support	Enable the Qt3Support libraries for Qt4. Note that this does not mean you can compile pure Qt3 programs with Qt4.
qt-dbus	c++0x	Build Qt using the C++11 standard
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	qpa	Build a window system agnostic implementation of Qt
qt-declarative	c++0x	Build Qt using the C++11 standard
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	private-headers	Install Qt declarative private headers required by Qt-creator QmlDesigner and QmlInspector plugins"
	qpa	Build a window system agnostic implementation of Qt
	qt3support	Enable the Qt3Support libraries for Qt4. Note that this does not mean you can compile pure Qt3 programs with Qt4.
	webkit	Build the WebView QML element
qt-demo	c++0x	Build Qt using the C++11 standard
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	qpa	Build a window system agnostic implementation of Qt
	qt3support	Enable the Qt3Support libraries for Qt4. Note that this does not mean you can compile pure Qt3 programs with Qt4.
qt-gui	c++0x	Build Qt using the C++11 standard
	egl	Use EGL instead of default GLX to manage OpenGL contexts on the desktop
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	glib	Enable dev-libs/glib eventloop support
	gtkstyle	Build a Qt style called GTK+ that mimics the active GTK+ theme
	private-headers	Install Qt declarative private headers required by Qt-creator QmlDesigner and QmlInspector plugins"
	qpa	Build a window system agnostic implementation of Qt
	qt3support	Enable the Qt3Support libraries for Qt4. Note that this does not mean you can compile pure Qt3 programs with Qt4.
	raster	Use the alternative raster graphicssystem as default rendering engine
	trace	Build the new 'trace' graphicsssytem engine which allows to record all drawing operations into a trace buffer. Later it can be replayed with the qttracereplay utility
qt-meta	kde	Select media-sound/phonon as phonon variant, needed for KDE
	openvg	Build the Qt OpenVG module
	qt3support	Enable the Qt3Support library for Qt4
qt-mobility	bearer	Build the QtBearer module
	bluetooth	Enable Bluetooth support in QtConnectivity and QtSystemInfo modules
	connectivity	Build the QtConnectivity module
	contacts	Build the QtContacts module
	feedback	Build the QtFeedback module
	gallery	Build the QtGallery module
	location	Build the QtLocation module
	messaging	Build the QtMessaging module
	multimedia	Build the QtMultimediaKit module
	networkmanager	Enable NetworkManager support in QtBearer and QtSystemInfo modules
	opengl	Enable OpenGL support in QtMultimediaKit module
	organizer	Build the QtOrganizer module
	publishsubscribe	Build the QtPublishSubscribe module
	pulseaudio	Enable PulseAudio support in QtMultimediaKit module
	qml	Build QML bindings
	sensors	Build the QtSensors module
	serviceframework	Build the QtServiceFramework module
	systeminfo	Build the QtSystemInfo module
	tools	Build various useful tools (e.g.: qcrmlgen, servicexmlgen, vsexplorer, ...)
	versit	Build the QtVersit module
qt-multimedia	c++0x	Build Qt using the C++11 standard
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	qpa	Build a window system agnostic implementation of Qt
qt-opengl	c++0x	Build Qt using the C++11 standard
	egl	Use EGL instead of default GLX to manage OpenGL contexts on the desktop
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	qpa	Build a window system agnostic implementation of Qt
	qt3support	Enable the Qt3Support libraries for Qt4
qt-openvg	c++0x	Build Qt using the C++11 standard
	exceptions	Build with support for exceptions
	qpa	Build a window system agnostic implementation of Qt
	qt3support	Enable the Qt3Support libraries for Qt4
qt-phonon	c++0x	Build Qt using the C++11 standard
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	qpa	Build a window system agnostic implementation of Qt
	qt3support	Enable the Qt3Support libraries for Qt4. Note that this does not mean you can compile pure Qt3 programs with Qt4.
qt-qt3support	c++0x	Build Qt using the C++11 standard
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	kde	Select media-sound/phonon as phonon variant needed for kde
	phonon	Enable phonon configuration dialog in qtconfig
	qpa	Build a window system agnostic implementation of Qt
qt-script	c++0x	Build Qt using the C++11 standard
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	jit	Enables JIT for Javascript usage inside Qt
	private-headers	Install Qt declarative private headers required by Qt-creator QmlDesigner and QmlInspector plugins"
	qpa	Build a window system agnostic implementation of Qt
qt-sql	c++0x	Build Qt using the C++11 standard
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	qpa	Build a window system agnostic implementation of Qt
	qt3support	Enable the Qt3Support libraries for Qt4
qt-svg	c++0x	Build Qt using the C++11 standard
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	qpa	Build a window system agnostic implementation of Qt
qt-test	c++0x	Build Qt using the C++11 standard
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	qpa	Build a window system agnostic implementation of Qt
qt-webkit	c++0x	Build Qt using the C++11 standard
	exceptions	Add support for exceptions - like catching them inside the event loop (recommended by Nokia)
	jit	Enables JIT for Javascript usage inside Qt
	kde	Select media-sound/phonon as phonon variant needed for kde
	qpa	Build a window system agnostic implementation of Qt
qt-xmlpatterns	c++0x	Build Qt using the C++11 standard
qt-xmlpatterns	qpa	Build a window system agnostic implementation of Qt
vte	glade	Provide integration with dev-util/glade.
vte	introspection	Use dev-libs/gobject-introspection for introspection
wxGTK	gnome	Use gnome-base/libgnomeprintui for printing tasks.
	gstreamer	Enable the wxMediaCtrl class for playing audio and video through gstreamer.
	sdl	Use Simple Directmedia Layer (media-libs/libsdl) for audio.

x11-misc

Package	Flag	Description
bmpanel	libev	Use the libev event loop interface
bmpanel	libevent	Use the libevent event loop interface
colord	gusb	Enable dev-libs/libgusb support, needed for colorimeter drivers
	introspection	Use dev-libs/gobject-introspection for introspection
	vala	Generate bindings for dev-lang/vala
etm	ical	Enable export of ical format files by depending on dev-python/icalendar
fbpager	xrender	Enable transparency support via x11-libs/libXrender
google-gadgets	soup	Enables XML HTTP request extension based on net-libs/libsoup
google-gadgets	webkit	Enables browser element and script runtime based on net-libs/webkit-gtk
lightdm	branding	Replace original gnome background with one from Gentoo ten project
lightdm	introspection	Use dev-libs/gobject-introspection for introspection
obconf	lxde	Add wrapper for LXDE environment
rednotebook	libyaml	enable libyaml support
rednotebook	webkit	enable previews using webkit engine
redshift	geoclue	Control dependency on app-misc/geoclue
revelation	applet	Enable applet for gnome-base/gnome-panel
rss-glx	quesoglc	Enable support for OpenGL Character Renderer
shutter	drawing	Enables drawing tool
shutter	webphoto	Enables screenshots of websites
slim	consolekit	Enable native consolekit support
spacefm	fam	Disable inotify and use fam or gamin instead
tint2	battery	Enable battery status plugin
	examples	Install tint2rc examples
	tint2conf	Build/Install tint2conf as well
tinynotify-send	symlink	Symlink tinynotify-send to notify-send.
vnc2swf	x11vnc	Install script that depends on x11vnc
wbar	gtk	Enables the gtk-based wbar-config GUI
x11vnc	system-libvncserver	Build x11vnc against the system libvncserver (experimental)
x11vnc	tk	Support the simple tcl/tk -gui option
xlockmore	xlockrc	Enables xlockrc for people without PAM
xmobar	mail	Support the mail plugin. Pulls dependency dev-haskell/hinotify.
xscreensaver	new-login	Enable New Login button using gdmflexiserver (gnome-base/gdm) or kdmctl (kde-base/kdm)
zim	screenshot	Enable screenshot support (using media-gfx/scrot)

x11-plugins

Package	Flag	Description
bfm	gkrellm	Enable building of app-admin/gkrellm module
compiz-plugins-extra	gconf	Install GConf schemas for the plugins, needed when using the GConf-based configuration backend in x11-wm/compiz.
compiz-plugins-main	gconf	Install GConf schemas for the plugins, needed when using the GConf-based configuration backend in x11-wm/compiz.
enigmail	custom-optimization	Enable user CFLAGS
enigmail	system-sqlite	Use the system-wide dev-db/sqlite installation with secure-delete enabled
pidgin-mbpurple	twitgin	Enable graphical plugin for Gtk+ interface of Pidgin.
pidgin-sipe	voice	Enable experimental voice/video support
purple-plugin_pack	talkfilters	Enable support for app-text/talklfilters
screenlets	svg	Highly Recommended: Enable SVG graphics via dev-python/librsvg-python
wmfire	session	Enable session management
wmsysmon	high-ints	Enable support for monitoring 24 interrupts. Useful on SMP machines

x11-terms

Package	Flag	Description
aterm	background	Enable background image support via media-libs/libafterimage
aterm	xgetdefault	Enable resources via X instead of aterm small version
eterm	escreen	Enable built-in app-misc/screen support
hanterm	utempter	Records user logins. Useful on multi-user systems
mlterm	ibus	Enable app-i18n/ibus support
	libssh2	Enable net-libs/libssh2 support
	scim	Enable app-i18n/scim support
	uim	Enable app-i18n/uim support
mrxvt	menubar	Enable mrxvt menubar
mrxvt	utempter	REcords user logins. Useful on multi-user systems
rxvt	linuxkeys	Define LINUX_KEYS (changes Home/End key)
rxvt	xgetdefault	Enable resources via X instead of rxvt small version
rxvt-unicode	256-color	Enable 256 color support
	afterimage	Enable transparency support using media-libs/libafterimage (deprecated in 9.14)
	alt-font-width	Calculate the font width using a different method
	blink	Enable blinking text
	buffer-on-clear	Store visible output to history buffer when clearing the screen with ctrl-l. Read https://bbs.archlinux.org/viewtopic.php?id=129302
	fading-colors	Enable colors fading when off focus
	focused-urgency	Enable the urgent flag when a terminal window is focused
	font-styles	Enable support for bold and italic fonts
	force-hints	Force WM hints on rxvt-unicode's geometry. Read http://bugs.gentoo.org/show_bug.cgi?id=346553
	iso14755	Enable ISO-14755 support
	mousewheel	Enable scrolling via mouse wheel or buttons 4 and 5
	perl	Enable perl script support. You can still disable this at runtime with -pe ""
	pixbuf	Enable transparency support using gtk's pixbuf
	secondary-wheel	Support for wheel scrolling on secondary screens (like mutt). Read http://lists.schmorp.de/pipermail/rxvt-unicode/2011q4/001491.html
	unicode3	Use 21 instead of 16 bits to represent unicode characters
	wcwidth	Enable wide char width support
xterm	toolbar	Enable the xterm toolbar to be built

x11-themes

Package	Flag	Description
gentoo-artwork	grub	Install extra sys-boot/grub themes
	icons	Install icons
	lilo	Install extra sys-boot/lilo themes
	pixmaps	Install pixmaps
gtk-engines-murrine	animation-rtl	Progressbar animation from right to left
gtk-engines-murrine	themes	Pull in themes via x11-themes/murrine-themes
gtk-engines-nodoka	animation-rtl	Progressbar animation from right to left
gtk-engines-qtcurve	firefox3	Install GUI theme tweaks for version 3 of www-client/firefox
gtk-engines-qtcurve	mozilla	Install GUI theme tweaks for mozilla based browsers www-client/firefox
light-themes	gtk3	Support GTK 3.x, too
qtcurve-qt4	kde	Enable KDE4 support. This adds a QtCurve configuration module to KDE's SystemSettings.
qtcurve-qt4	windeco	Enable window decoration for KWin.
redhat-artwork	audacious	Install media-sound/audacious theme
	cursors	Install Bluecurve cursors
	gdm	Install Bluecurve gnome-base/gdm theme
	icons	Install Bluecurve icons
	kdm	Install Bluecurve kde-base/kdm theme
	nautilus	Install Bluecurve gnome-base/nautilus icons
skinenigmang-logos	dxr3	Install logos for lower osd color depth on dxr3 cards

x11-wm

Package	Flag	Description
compiz	fuse	Enables support for the filesystem in userspace plugin through sys-fs/fuse.
compiz	gconf	Enable the GConf-based configuration backend; it is not required to work with GNOME, and might actually be faster if it's not used.
compiz-fusion	emerald	Install the x11-wm/emerald package.
compiz-fusion	unsupported	Install the x11-plugins/compiz-fusion-plugins-unsupported package.
echinus	xrandr	Enable support for multihead configuration
enlightenment	pango	Enable pango font rendering
enlightenment	xrandr	Enable support for the X xrandr extension
fluxbox	bidi	Enable bidirectional language support with dev-libs/fribidi
	newmousefocus	Patches the focus model to the upcoming 1.1.2 model, which adds a new 'StrictMouseFocus' mode
	slit	Enables the fluxbox slit (or dock)
	toolbar	Enables the fluxbox toolbar
fvwm	gtk2-perl	Enable GTK2 Perl bindings
	lock	Enable screen locking
	netpbm	Enable NetPBM support (used by FvwmScript-ScreenDump)
	rplay	Enable rplay support
	stroke	Mouse Gesture support
matchbox-common	pda	Support for pda folders
matchbox-desktop	dnotify	Use the linux kernel directory notification feature.
matchbox-panel	dnotify	Use the linux kernel directory notification feature.
matchbox-panel	lowres	Optimize for low resolution screens.
muffin	introspection	Use dev-libs/gobject-introspection for introspection
musca	apis	Optionally install the experimental `apis' window manager
musca	xlisten	Optionally install the xlisten utility
mutter	introspection	Use dev-libs/gobject-introspection for introspection
openbox	session	Enables support for session managers
ratpoison	history	Use sys-libs/readline for history handling
sawfish	pango	Enable pango support
stumpwm	clisp	Use CLISP for the runtime
stumpwm	sbcl	Use SBCL for the runtime
subtle	xrandr	Enable support for the X RandR extension
subtle	xtest	Enable support for the XTest extension
vtwm	rplay	Enable rplay support, needed for sound.
windowmaker	modelock	Enable XKB language status lock support. README says: "If you don't know what it is you probably don't need it."
windowmaker	vdesktop	Enable dynamic virtual desktop (conflicts with software that works on the edges of the screen)
xpra	parti	Runtime support for partioning window manager
	server	Build server-side code
	ssh	Runtime support for secure shell communication

xfce-base

Package	Flag	Description
libxfce4ui	glade	Build support for Glade 3's GtkBuilder implementation
libxfcegui4	glade	Build glade bindings
xfce-utils	lock	Enable screen locking
xfce4-session	consolekit	Enable authentication support using sys-auth/consolekit
xfce4-session	gnome-keyring	Enable password storage support using gnome-base/gnome-keyring
xfce4-settings	libcanberra	Enable sound event support using media-libs/libcanberra
xfce4-settings	xklavier	Enable keyboard layout selection support using x11-libs/libxklavier
xfdesktop	thunar	Build support for desktop icons (for example, launchers and folders)

xfce-extra

Package	Flag	Description
thunar-vcs-plugin	git	Enable dev-vcs/git support
tumbler	odf	Enable support for .odf thumbnailers by using gnome-extra/libgsf
xfce4-mpc-plugin	libmpd	Build using media-libs/libmpd backend, instead of native fallback which is preferred
xfce4-playercontrol-plugin	audacious	Enable Audacious support
xfce4-playercontrol-plugin	mpd	Enable Music Player Daemon support
xfce4-soundmenu-plugin	glyr	Enable music metadata searchengine support using media-libs/glyr
xfce4-soundmenu-plugin	lastfm	Enable last.fm support using media-libs/libclastfm

Page updated February 4, 2012

Summary: Global and local USE flags used by Gentoo

Xavier Neys

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