USE flag index

---

Global USE flags

Flag	Description
3dfx	Enable support for Voodoo chipsets, also called as 3DFX and TDFX
X	Add support for X11
Xaw3d	Add support for the 3d athena widget set
a52	Enable support for decoding ATSC A/52 streams used in DVD
aac	Enable support for MPEG-4 AAC Audio
aalib	Add support for media-libs/aalib (ASCII-Graphics Library)
accessibility	Add support for accessibility (eg 'at-spi' library)
acl	Add support for Access Control Lists
acpi	Add support for Advanced Configuration and Power Interface
adns	Add support for asynchronous DNS resolution
afs	Add OpenAFS support (distributed file system)
alsa	Add support for media-libs/alsa-lib (Advanced Linux Sound Architecture)
altivec	Add support for optimizations for G4 and G5/ppc970 processors
ao	Use libao audio output library for sound playback
apache2	Add Apache2 support
aqua	Include support for the Mac OS X Aqua (Carbon/Cocoa) GUI
atm	Enable Asynchronous Transfer Mode protocol support
appindicator	Build in support for notifications using the libindicate or libappindicator plugin
audiofile	Add support for libaudiofile where applicable
audit	Enable support for Linux audit subsystem using sys-process/audit
ayatana	Build in support for Ayatana notification using the libindicate or libappindicator plugin
bash-completion	Enable bash-completion support
berkdb	Add support for sys-libs/db (Berkeley DB for MySQL)
bidi	Enable bidirectional language support
big-endian	Big-endian toolchain support
bindist	Flag to enable or disable options for prebuilt (GRP) packages (eg. due to licensing issues)
blas	Add support for the virtual/blas numerical library
bluetooth	Enable Bluetooth Support
branding	Enable Gentoo specific branding
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	Add support for calendars (not using mcal!)
canna	Add support for the Canna kana to kanji conversion engine
caps	Use Linux capabilities library to control privilege
cdb	Add support for the CDB database engine from the author of qmail
cdda	Add Compact Disk Digital Audio (Standard Audio CD) support
cddb	Access cddb servers to retrieve and submit information about compact disks
cdinstall	Copy files from the CD rather than asking the user to copy them, mostly used with games
cdr	Add support for CD writer hardware
cgi	Add CGI script support
cjk	Add support for Multi-byte character languages (Chinese, Japanese, Korean)
clamav	Add support for Clam AntiVirus software (usually with a plugin)
colord	Support color management using x11-misc/colord
connman	Add support for net-misc/connman
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
css	Enable reading of encrypted DVDs
cups	Add support for CUPS (Common Unix Printing System)
curl	Add support for client-side URL transfer library
custom-cflags	Build with user-specified CFLAGS (unsupported)
cvs	Enable CVS (Concurrent Versions System) integration
cxx	Build support for C++ (bindings, extra libraries, code generation, ...)
dbi	Enable dev-db/libdbi (database-independent abstraction layer) support
dbm	Add support for generic DBM databases
dbus	Enable dbus support for anything that needs it (gpsd, gnomemeeting, etc)
debug	Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces
dedicated	Add support for dedicated game servers (some packages do not provide clients and servers at the same time)
dga	Add DGA (Direct Graphic Access) support for X
djvu	Support DjVu, a PDF-like document format esp. suited for scanned documents
doc	Add 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	Enable DTS Coherent Acoustics decoder support
dv	Enable support for a codec used by many camcorders
dvb	Add support for DVB (Digital Video Broadcasting)
dvd	Add support for DVDs
dvdr	Add support for DVD writer hardware (e.g. in xcdroast)
eds	Enable support for Evolution-Data-Server (EDS)
elogind	Enable session tracking via sys-auth/elogind
emacs	Add support for GNU Emacs
emboss	Add support for the European Molecular Biology Open Software Suite
encode	Add support for encoding of audio or video files
examples	Install examples, usually source code
exif	Add 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	Add framebuffer support for the console, via the kernel
ffmpeg	Enable ffmpeg/libav-based audio/video codec support
fftw	Use FFTW library for computing Fourier transforms
filecaps	Use Linux file capabilities to control privilege rather than set*id (this is orthogonal to USE=caps which uses capabilities at runtime e.g. libcap)
firebird	Add support for the Firebird relational database
flac	Add support for FLAC: Free Lossless Audio Codec
fltk	Add support for the Fast Light Toolkit gui interface
fontconfig	Support for configuring and customizing font access via media-libs/fontconfig
fortran	Add support for fortran
freetds	Add support for the TDS protocol to connect to MSSQL/Sybase databases
freewnn	Add support for FreeWnn kana to kanji conversion engine
ftp	Add FTP (File Transfer Protocol) support
gd	Add support for media-libs/gd (to generate graphics on the fly)
gdbm	Add support for sys-libs/gdbm (GNU database libraries)
geoip	Add geoip support for country and city lookup based on IPs
geolocation	Enable physical position determination
ggi	Add support for media-libs/libggi (non-X video api/drivers)
gif	Add GIF image support
gimp	Build a plugin for the GIMP
git	Enable git (version control system) support
gles2-only	Use GLES 2.0 or later instead of full OpenGL
glut	Build an OpenGL plugin using the GLUT library
gmp	Add support for dev-libs/gmp (GNU MP library)
gnome	Add GNOME support
gnome-keyring	Enable support for storing passwords via gnome-keyring
gnuplot	Enable support for gnuplot (data and function plotting)
gnutls	Prefer net-libs/gnutls as SSL/TLS provider (ineffective with USE=-ssl)
gphoto2	Add digital camera support
gpm	Add support for sys-libs/gpm (Console-based mouse driver)
gps	Add support for Global Positioning System
graphicsmagick	Build and link against GraphicsMagick instead of ImageMagick (requires USE=imagemagick if optional)
graphviz	Add support for the Graphviz library
gsl	Use the GNU scientific library for calculations
gsm	Add support for the gsm lossy speech compression codec
gstreamer	Add support for media-libs/gstreamer (Streaming media)
gtk	Add support for x11-libs/gtk+ (The GIMP Toolkit)
gtk-doc	Build and install gtk-doc based developer documentation for dev-util/devhelp, IDE and offline use
gui	Enable support for a graphical user interface
guile	Add support for the guile Scheme interpreter
gzip	Compress files with Lempel-Ziv coding (LZ77)
handbook	Enable handbooks generation for packages by KDE
hardened	Activate default security enhancements for toolchain (gcc, glibc, binutils)
hddtemp	Enable monitoring of hdd temperature (app-admin/hddtemp)
hdf5	Add support for the Hierarchical Data Format v5
headers-only	Install only C headers instead of whole package. Mainly used by sys-devel/crossdev for toolchain bootstrap.
hscolour	Include 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
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	Enable optional support for the ImageMagick or GraphicsMagick image converter
imap	Add support for IMAP (Internet Mail Application Protocol)
imlib	Add support for imlib, an image loading and rendering library
infiniband	Enable Infiniband RDMA transport support
inotify	Enable inotify filesystem monitoring support
introspection	Add support for GObject based introspection
iodbc	Add 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	Add support for IP version 6
jack	Add support for the JACK Audio Connection Kit
java	Add support for Java
javascript	Enable javascript support
jbig	Enable jbig-kit support for tiff, Hylafax, ImageMagick, etc
jemalloc	Use dev-libs/jemalloc for memory management
jit	Enable just-in-time compilation for improved performance. May prevent use of some PaX memory protection features in Gentoo Hardened.
joystick	Add support for joysticks in all packages
jpeg	Add JPEG image support
jpeg2k	Support for JPEG 2000, a wavelet-based image compression format
kde	Add support for software made by KDE, a free software community
kerberos	Add kerberos support
ladspa	Enable the ability to support ladspa plugins
lame	Prefer using LAME libraries for MP3 encoding support
lapack	Add support for the virtual/lapack numerical library
lash	Add LASH Audio Session Handler support
latex	Add support for LaTeX (typesetting package)
lcms	Add lcms support (color management engine)
ldap	Add LDAP support (Lightweight Directory Access Protocol)
libass	SRT/SSA/ASS (SubRip / SubStation Alpha) subtitle support
libav	Prefer libav over ffmpeg whenever both are supported
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
libressl	Use dev-libs/libressl instead of dev-libs/openssl when applicable (see also the ssl useflag)
libsamplerate	Build with support for converting sample rates using libsamplerate
libwww	Add libwww support (General purpose WEB API)
lirc	Add 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	Add linux lm-sensors (hardware sensors) support
lua	Enable Lua scripting support
luajit	Use dev-lang/luajit instead of dev-lang/lua (ineffective with USE=-lua)
lzma	Support for LZMA (de)compression algorithm
lz4	Enable support for lz4 compression (as implemented in app-arch/lz4)
lzo	Enable support for lzo compression
m17n-lib	Enable m17n-lib support
mad	Add support for mad (high-quality mp3 decoder library and cli frontend)
magic	Add support for file type detection via magic bytes (usually via libmagic from sys-apps/file)
maildir	Add support for maildir (~/.maildir) style mail spools
matroska	Add support for the matroska container format (extensions .mkv, .mka and .mks)
mbox	Add support for mbox (/var/spool/mail) style mail spools
memcached	Add support for memcached
mhash	Add support for the mhash library
mikmod	Add libmikmod support to allow playing of SoundTracker-style music files
milter	Add sendmail mail filter (milter) support
minimal	Install a very minimal build (disables, for example, plugins, fonts, most drivers, non-critical features)
mmap	Add mmap (memory map) support
mms	Support for Microsoft Media Server (MMS) streams
mng	Add support for libmng (MNG images)
modplug	Add libmodplug support for playing SoundTracker-style music files
modules	Build the kernel modules
mono	Build Mono bindings to support dotnet type stuff
motif	Add support for the Motif toolkit
mp3	Add support for reading mp3 files
mp4	Support for MP4 container format
mpeg	Add libmpeg3 support to various packages
mpi	Add MPI (Message Passing Interface) layer to the apps that support it
mplayer	Enable mplayer support for playback or encoding
mssql	Add support for Microsoft SQL Server database
mtp	Enable support for Media Transfer Protocol
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	Add mySQL Database support
mysqli	Add support for the improved mySQL libraries
nas	Add support for network audio sound
ncurses	Add ncurses support (console display library)
neXt	Enable neXt toolkit
neon	Enable optimization support for ARM NEON processors
netcdf	Enable NetCDF data format support
networkmanager	Enable net-misc/networkmanager support
nis	Support for NIS/YP services
nls	Add 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
nsplugin	Build plugin for browsers supporting the Netscape plugin architecture (that is almost any modern browser)
ocaml	Add support/bindings for the Ocaml language
ocamlopt	Enable ocamlopt support (ocaml native code compiler) -- Produces faster programs (Warning: you have to disable/enable it at a global scale)
oci8	Add 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	Add ODBC Support (Open DataBase Connectivity)
offensive	Enable potentially offensive items in packages
ofx	Enable support for importing (and exporting) OFX (Open Financial eXchange) data files
ogg	Add support for the Ogg container format (commonly used by Vorbis, Theora and flac)
openal	Add support for the Open Audio Library
openexr	Support for the OpenEXR graphics file format
opengl	Add support for OpenGL (3D graphics)
openmp	Build support for the OpenMP (support parallel computing), requires >=sys-devel/gcc-4.2 built with USE="openmp"
opus	Enable Opus audio codec support
oracle	Enable Oracle Database support
orc	Use dev-lang/orc for just-in-time optimization of array operations
osc	Enable support for Open Sound Control
oss	Add support for OSS (Open Sound System)
pam	Add 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	Add support for PCMCIA slots/devices found on laptop computers
pcre	Add support for Perl Compatible Regular Expressions
pda	Add support for portable devices
pdf	Add general support for PDF (Portable Document Format), this replaces the pdflib and cpdflib flags
perl	Add optional support/bindings for the Perl language
php	Include support for the PHP language
pie	Build programs as Position Independent Executables (a security hardening technique)
plasma	Build optional KDE plasma addons
plotutils	Add support for plotutils (library for 2-D vector graphics)
png	Add support for libpng (PNG images)
policykit	Enable PolicyKit authentication support
portaudio	Add support for the crossplatform portaudio audio API
posix	Add support for POSIX-compatible functions
postgres	Add support for the postgresql database
postscript	Enable support for the PostScript language (often with ghostscript-gpl or libspectre)
ppds	Add support for automatically generated ppd (printing driver) files
prefix	Defines if a Gentoo Prefix offset installation is used
profile	Add support for software performance analysis (will likely vary from ebuild to ebuild)
pulseaudio	Add support for PulseAudio sound server
python	Add optional support/bindings for the Python language
qdbm	Add support for the qdbm (Quick Database Manager) library
qmail-spp	Add support for qmail SMTP plugins
qt5	Add support for the Qt 5 application and UI framework
quicktime	Add support for OpenQuickTime
radius	Add support for RADIUS authentication
raw	Add support for raw image formats
rdp	Enables RDP/Remote Desktop support
readline	Enable support for libreadline, a GNU line-editing library that almost everyone wants
recode	Enable support for the GNU recode library
rss	Enable support for RSS feeds
ruby	Add support/bindings for the Ruby language
samba	Add support for SAMBA (Windows File and Printer sharing)
sasl	Add 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	Add support for scanner hardware (e.g. build the sane frontend in kdegraphics)
sctp	Support for Stream Control Transmission Protocol
sdl	Add support for Simple Direct Layer (media library)
seccomp	Enable seccomp (secure computing mode) to perform system call filtering at runtime to increase security of programs
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	Add persistent session support
skey	Enable S/Key (Single use password) authentication support
slang	Add support for the slang text display library (it's like ncurses, but different)
slp	Add Service Locator Protocol support
smartcard	Enable smartcard support
smp	Enable support for multiprocessors or multicore systems
snappy	Enable support for Snappy compression (as implemented in app-arch/snappy)
sndfile	Add support for libsndfile
snmp	Add support for the Simple Network Management Protocol if available
soap	Add support for SOAP (Simple Object Access Protocol)
sockets	Add support for tcp/ip sockets
socks5	Add support for the socks5 proxy
sound	Enable sound support
source	Zip the sources and install them
sox	Add support for Sound eXchange (SoX)
speex	Add support for the speex audio codec (used for speech)
spell	Add dictionary support
split-usr	Enable behavior to support maintaining /bin, /lib*, /sbin and /usr/sbin separately from /usr/bin and /usr/lib*
sqlite	Add support for sqlite - embedded sql database
ssl	Add support for SSL/TLS connections (Secure Socket Layer / Transport Layer Security)
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 versions of dynamic libraries as well
subversion	Enable subversion (version control system) support
suid	Enable setuid root program, with potential security risks
svg	Add support for SVG (Scalable Vector Graphics)
svga	Add support for SVGAlib (graphics library)
symlink	Force kernel ebuilds to automatically update the /usr/src/linux symlink
syslog	Enable support for syslog
systemd	Enable use of systemd-specific libraries and features like socket activation or session tracking
szip	Use the szip compression library
taglib	Enable tagging support with taglib
tcl	Add support the Tcl language
tcmalloc	Use the dev-util/google-perftools libraries to replace the malloc() implementation with a possibly faster one
tcpd	Add support for TCP wrappers
telemetry	Send anonymized usage information to upstream so they can better understand our users
test	Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently)
theora	Add support for the Theora Video Compression Codec
threads	Add threads support for various packages. Usually pthreads
tidy	Add support for HTML Tidy
tiff	Add support for the TIFF image format
timidity	Build with Timidity++ (MIDI sequencer) support
tk	Add support for Tk GUI toolkit
truetype	Add support for FreeType and/or FreeType2 fonts
uclibc	Enable uclibc specific patches and build or link uclibc
udev	Enable virtual/udev integration (device discovery, power and storage device support, etc)
udisks	Enable storage management support (automounting, volume monitoring, etc)
unicode	Add support for Unicode
unwind	Add support for call stack unwinding and function name resolution
upnp	Enable UPnP port mapping support
upnp-av	Enable UPnP audio/video streaming support
upower	Enable power management support
usb	Add USB support to applications that have optional USB support (e.g. cups)
v4l	Enable support for video4linux (using linux-headers or userspace libv4l libraries)
vaapi	Enable Video Acceleration API for hardware decoding
vala	Enable bindings for dev-lang/vala
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
vdpau	Enable the Video Decode and Presentation API for Unix acceleration interface
vhosts	Add 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	Add support for the OggVorbis audio codec
wavpack	Add support for wavpack audio compression tools
wayland	Enable dev-libs/wayland backend
webkit	Add support for the WebKit HTML rendering/layout engine
webp	Add support for the WebP image format
wifi	Enable wireless network functions
wmf	Add support for the Windows Metafile vector image format
wxwidgets	Add support for wxWidgets/wxGTK GUI toolkit
x264	Enable h264 encoding using x264
xattr	Add 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	Add 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 querying multi-monitor screen geometry through the Xinerama API
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	Add support for XPM graphics format
xscreensaver	Add support for XScreenSaver extension
xv	Add in optional support for the Xvideo extension (an X API for video playback)
xvid	Add support for xvid.org's open-source mpeg-4 codec
zeroconf	Support for DNS Service Discovery (DNS-SD)
zip	Enable support for ZIP archives
zlib	Add support for zlib (de)compression
zsh-completion	Enable zsh completion support
zstd	Enable support for ZSTD compression

Local USE flags

acct-user

git

gitea	Set home directory for git hosting via www-apps/gitea.
gitolite	Set home directory for git hosting via dev-vcs/gitolite or dev-vcs/gitolite-gentoo.

app-accessibility

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
louis	Use braille tranlator dev-libs/liblouis
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

flite

voices	Install synthetic voices

freetts

jsapi	build Java Speech API (JSAPI)
mbrola	Adds support for mbrola voices

orca

braille	Enable braille support

simon

opencv	Use media-libs/opencv
pim	Enable support for KDE PIM resources integration
sphinx	Build sphinx backend (pulls app-accessibility/julius if disabled

speech-dispatcher

espeak	Adds support for espeak speech engine
flite	Adds support for flite speech engine

speechd-el

brltty	brltty support

app-admin

calamares

pythonqt	Enable PythonQt-based module interface

clsync

cgroups	Use cgroups to limit /dev access.
cluster	Enable clustering support (allows master-master clsync on multiple hosts). Not fully implemented yet.
control-socket	Enable AF_UNIX control socket support.
extra-debug	Enable extra debugging. This will hurt performance badly. Be ready for tons of output.
extra-hardened	Enable extra security checks. This will hurt performance.
gio	Enable GIO for FS monitoring (glib based alternative to inotify interface, not recommended; if both are compiled, may be selected at runtime).
highload-locks	Allows to use spinlocks for short delays instead of mutexes, but only on SMP systems.
namespaces	Enable namespaces isolation.

conky

apcupsd	Enable support for sys-power/apcupsd
bundled-toluapp	Enable support for bundled toluapp. This only makes sense in combination with the lua-* flags
cmus	Enable monitoring of music played by media-sound/cmus
eve	Enable support for the eve-online skill monitor
ical	Enable support for events from iCalendar (RFC 5545) files using dev-libs/libical
iostats	Enable support for per-task I/O statistics
irc	Enable support for displaying everything from an irc channel using net-libs/libircclient
lua-cairo	Enable if you want Lua Cairo bindings
lua-imlib	Enable if you want Lua Imlib2 bindings
lua-rsvg	Enable if you want Lua RSVG bindings
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 x11-drivers/nvidia-drivers
portmon	Enable support for tcp (ip4) port monitoring
thinkpad	Enable support for IBM/Lenovo notebooks
weather-metar	Enable support for metar weather service
webserver	Enable support to act as a webserver serving conkys output using net-libs/libmicrohttpd
xmms2	Enable monitoring of music played by media-sound/xmms2

conserver

freeipmi	Compile in FreeIPMI support via sys-libs/freeipmi

diamond

mongo	Enable MongoDB support
redis	Enable Redis support

diradm

automount	Support for automount data in LDAP
irixpasswd	Support for storing separate IRIX passwords

elektra

augeas	Enable plugin for reading and writing configuration files with help from Augeas
ini	Enable new, advanced ini support
simpleini	Enable simpleini support
uname	Enable uname information for the key database
yajl	Enable yajl support

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

glance

swift	Adds swift storage support

gtkdiskfree

gtk2	Support GTK+ 2.x instead of GTK+ 3.x

hddtemp

network-cron	Monthly cronjob to update hddtemp.db.

keepass

aot	Generate native code at build time, rather than runtime.

keepassxc

autotype	Add support to autotype the passwords into other applications
browser	Enables browser plugin support
ccache	Use dev-util/ccache to build keepassxc
keeshare	Enable KeeShare sharing integration
network	Enable network support
yubikey	Enable database unlocking via YubiKey.

lastpass-cli

X	Use x11-misc/xclip or x11-misc/xsel to copy passwords to the clipboard.
pinentry	Use app-crypt/pinentry to prompt for passwords.

logrotate

acl	Installs acl support
cron	Installs cron file
selinux	Installs Security Enhanced Linux support

logstash-bin

x-pack	Enable additional features (may need a license)

mcollective

client	Install client utilities

mms-agent

monitoring	Install the monitoring agent

openrc-settingsd

systemd	Use the versions of dbus and polkit files provided by sys-apps/systemd

pass

X	Use x11-misc/xclip to copy passwords to the clipboard.
dmenu	Add support for x11-misc/dmenu with the 'passmenu' program.
fish-completion	Enable fish completion support.
git	Use dev-vcs/git for password revisions.
importers	Allow importing passwords from other password managers using various contributed scripts.

pass-otp

qrcode	Add support for qrcodes using media-gfx/qrencode

passwordsafe

minimal	Avoid collision with app-misc/pwsafe
qr	Enable QR code password display
xml	Enable XML import support
xvkbd	Install x11-misc/xvkbd on-screen keyboard
yubikey	Enable support for Yubikey

prelude-manager

dbx	Enables Prelude Manager storing Prelude alerts into database through dev-libs/libpreludedb .
tcpwrapper	Enables Prelude Manager using tcp wrapper. It requires sys-apps/tcp-wrappers .

puppet

augeas	Enable augeas support
diff	Enable diff support
rrdtool	Enable rrdtool support
shadow	Enable shadow support

puppet-agent

puppetdb	Adds puppetdb support

puppetserver

puppetdb	Adds support for connecting to puppetdb

pwgen

livecd	Install init script for root password scrambling on boot

rsyslog

clickhouse	Build the ClickHouse output module (requires net-misc/curl)
curl	Enable http_request() function in RainerScript (requires net-misc/curl)
dbi	Build the general database output module (requires dev-db/libdbi)
elasticsearch	Build the Elasticsearch output module (requires net-misc/curl)
gcrypt	Add support for encrypted log files using dev-libs/libgcrypt
gnutls	Build the GnuTLS network stream driver (requires net-libs/gnutls)
kafka	Build the Apache Kafka input/output module (requires dev-libs/librdkafka)
kerberos	Build the GSSAPI input and output module (requires virtual/krb5)
kubernetes	Build the kubernetes modify plugin (requires net-misc/curl)
libressl	Use dev-libs/libressl instead of dev-libs/openssl (you still need to enable functionality which requires OpenSSL)
mdblookup	Build the MaxMind DB lookup message modify plugin using dev-libs/libmaxminddb
mongodb	Build the MongoDB output module (requires dev-libs/mongo-c-driver)
mysql	Build the MySQL database output module (requires virtual/mysql)
normalize	Build the normalize modify module (requires dev-libs/libee and dev-libs/liblognorm)
omhttp	Build the http output module (requires net-misc/curl)
omhttpfs	Build the httpfs output module (requires net-misc/curl)
omudpspoof	Build the udpspoof output module (requires net-libs/libnet)
openssl	Build the OpenSSL network stream driver (requires dev-libs/openssl)
postgres	Build the PostgreSQL database output module (requires dev-db/postgresql)
rabbitmq	Build the RabbitMQ output module (requires net-libs/rabbitmq-c)
redis	Build the Redis output module using (requires dev-libs/hiredis)
relp	Build the Reliable Event Logging Protocol (RELP) output module (requires dev-libs/librelp)
rfc3195	Build the rfc3195 input module (requires dev-libs/liblogging)
rfc5424hmac	Build the rfc5424hmac modify module (requires dev-libs/openssl or dev-libs/libressl)
snmp	Build the snmp modify and output module (requires net-analyzer/net-snmp)
ssl	Add support for encrypted client/server communication (requires net-libs/gnutls)
systemd	Build the journal input and output module (requires sys-apps/systemd)
usertools	Installs the user tools (rsgtutil, rscryutil...) corresponding to the set USE flags
uuid	Include UUIDs in messages (requires sys-apps/util-linux)
xxhash	Enable xxHash support in fmhash module (requires dev-libs/xxhash)
zeromq	Build the ZeroMQ input and output modules (requires net-libs/czmq)

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
snort	Add support to interact with Snort IDE using net-analyzer/snortsam'

sagan-rules

lognorm	Install normalize rules support with dev-libs/liblognorm

salt

cheetah	Enable support for dev-python/cheetah3
cherrypy	Enable support for using cherrypy.
genshi	Enable support for dev-python/genshi
gnupg	Enable support for gnupg via python-gnupg.
keyring	Enable support for keyrings via python-keyring.
libcloud	Enable salt-cloud support via libcloud.
libvirt	Support managing virtual machines with app-emulation/libvirt.
mako	Add support for using the mako template engine for parsing salt states.
mongodb	Support returning data to a mongodb server.
neutron	Support the OpenStack neutron network service.
nova	Enable support for the OpenStack Nova API
openssl	Add support for using TLS via OpenSSL.
portage	Add support for package state enforcement using sys-apps/portage
raet	Add support for the new RAET transport.
redis	Support returning data to a redis database.
zeromq	Add support for the zeromq transport.

sudo

gcrypt	Use message digest functions from dev-libs/libgcrypt instead of sudo's
libressl	Use message digest functions from dev-libs/libressl instead of sudo's
offensive	Let sudo print insults when the user types the wrong password
secure-path	Replace PATH variable with compile time secure paths
sendmail	Allow sudo to send emails with sendmail
sssd	Add System Security Services Daemon support
system-digest	Use message digest functions from dev-libs/libgcrypt, dev-libs/libressl or dev-libs/openssl instead of sudo's internal SHA2 implementation

sysklogd

logger	Build the logger program
logrotate	use app-admin/logrotate for rotating logs rather than custom cron scripts

syslog-ng

amqp	Enable support for AMQP destinations
geoip2	Add support for geo lookup based on IPs via dev-libs/libmaxminddb
http	Enable support for HTTP destinations
json	Enable support for JSON template formatting via dev-libs/json-c
kafka	Enable support for Kafka destinations
mongodb	Enable support for mongodb destinations
pacct	Enable support for reading Process Accounting files (EXPERIMENTAL, Linux only)
redis	Enable support for Redis destinations
smtp	Enable support for SMTP destinations
spoof-source	Enable support for spoofed source addresses

testdisk

ewf	Include ewf library
ntfs	Include the ability to read NTFS filesystems
reiserfs	Include reiserfs reading ability

tripwire

ssl	Adds support for Secure Socket Layer connections
static	Builds the package statically
tools	Installs app-admin/mktwpol, providing scripts for the installation/setup of tripwire, including generating the tripwire policy file and maintenance of the tripwire database

ulogd

json	Build JSON output plugin to save packets in JSON file format
nfacct	Build NFACCT input plugin to support traffic accounting via nfnetlink_acct
nfct	Build NFCT input plugin to support stateful flow-based logging via nfnetlink_conntrack
nflog	Build NFLOG input plugin to support stateless packet-based logging via nfnetlink_log
pcap	Build PCAP output plugin to save packets in libpcap file format
ulog	Build ULOG input plugin to support deprecated packet-based logging via ULOG target

vault

webui	Enable the Web UI

webalizer

xtended	Include the 404 extension

webapp-config

portage	Propagete python_targets dependencies to sys-apps/portage

app-antivirus

clamav

clamdtop	A Top like tool which shows what clamd is currently scanning amongst other things
clamsubmit	A tool to submit false positives / negatives
libclamav-only	Bypass building of libfreshclam and the ClamAV CLI applications.
metadata-analysis-api	Enables collection of file property metadata using ClamAV API for analysis by ClamAV bytecode programs.
xml	DMG and XAR support

clamtk

kde	Install the Dolphin plugin.
nautilus	Install the Nautilus plugin.
nemo	Install the Nemo plugin.
thunar	Install the Thunar plugin.

app-arch

cabextract

extras	Install experimental extra 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

deltarpm

system-zlib	Use system sys-libs/zlib. Do not enable features of rsync friendly.

dpkg

libmd	Use app-crypt/libmd library for message digest functions
update-alternatives	Install update-alternatives

dump

ermt	encrypted rmt support
uuid	Enable UUID support

engrampa

caja	Enable engrampa to integrate with mate-base/caja by providing entries in its context menu
packagekit	Enable support for installing via Packagekit based on archive type

file-roller

nautilus	Build contextual menu extension for gnome-base/nautilus.
packagekit	Enable support for the distro-neutral package manager GUI PackageKit

gzip

pic	disable optimized assembly code that is not PIC friendly

innoextract

debug	Enable debug logging and the --debug command-line option
lzma	Enable support for extracting lzma-compressed installers using app-arch/xz-utils

lbzip2

symlink	Install symlinks which override app-arch/bzip2 implementation

libarchive

blake2	Enable Blake2 hash support via app-crypt/libb2.
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
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

pigz

symlink	Install symlinks which override app-arch/gzip 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)

tar

minimal	just install `tar`

unzip

natspec	Use dev-libs/libnatspec to correctly decode non-ascii file names archived in Windows.

wimlib

fuse	Use fuse libraries
iso	Install app-cdr/cdrtools in order to prepare iso images
ntfs	Use libntfs-3g library from sys-fs/ntfs3g
openssl	Use the SHA-1 message digest from libcrypto instead of compilling another implementation
yasm	Use yasm assembler instead of nasm

xz-utils

extra-filters	Build additional filters that are not used in any of the default xz presets. This includes delta and BCJ coders, additional match finders and SHA256 checks.

zip

natspec	Use dev-libs/libnatspec to correctly decode non-ascii file names archived in Windows.

app-backup

amanda

ndmp	Support for the NDMP protocol
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
batch-insert	Enable batch insert into data base
logwatch	Install support files for logwatch

bareos

ceph	Enable ceph support
cephfs	Enable cephfs storage backend
clientonly	Only install file-daemon (client)
director	Install director
fastlz	Enable support vor lz4, lz4hc and lzfast using dev-libs/bareos-fastlzlib
glusterfs	Enable glusterfs storage backend
gnutls	When ssl is enabled, use GnuTLS instead of OpenSSL
jansson	JSON API support using JANSSON for director
lmdb	enable build of LMDB support for faster accurate backup
logwatch	Install support files for logwatch
ndmp	Enable support for NDMP (Network Data Management Protocol)
rados	Enable rados storage backend
rados-striper	Enable use of rados-striper
scsi-crypto	Enable low level SCSI crypto support
sql-pooling	Enable SQL pooling support
storage-daemon	Install storage daemon (bareos-sd)

btrbk

mbuffer	Use sys-block/mbuffer to enable progress bar and buffering/limiting functionality
pv	Use sys-apps/pv to enable progress bar functionality

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
gpg	Enables usage of asymetric crypto algorithms

duplicity

s3	Support for backing up to the Amazon S3 system

rear

udev	Have ReaR start backup when attaching your USB drive.

snapper

lvm	Enable LVM thinprovisioned snapshots support sys-fs/lvm2
xattr	Add support for getting and setting POSIX extended attributes, through sys-apps/attr.

tsm

tsm_cit	IBM Tivoli Common Inventory Technology
tsm_hw	Difference snapshot support for NetApp and N-Series file servers

zbackup

tartool	Install tartool utility

app-benchmarks

filebench

auto-completion	Enable command-line autocompletion using dev-libs/libtecla

httperf

idleconn	Build with the idleconn program

ioping

netdata	Add support for netdata

ramspeed

pic	Force shared libraries to be built as PIC (this is slower)

sysbench

aio	Enable libaio support

app-cdr

brasero

libburn	Enable dev-libs/libburn backend
nautilus	Build the gnome-base/nautilus extension
packagekit	Enable support for the distro-neutral package manager GUI PackageKit
playlist	Enable support for playlists through dev-libs/totem-pl-parser
tracker	Enable audio playlist search using the app-misc/tracker indexer

cdemu

cdemu-daemon	Pull app-cdr/cdemu-daemon dependency, useful in chroot environment (bug #315491). Do not disable until you know what you are doing.

dvdisaster

debug	Enable memory debugging.

gaffitter

scripts	Install additional gaffitter scripts for external programs

mirage2iso

pinentry	Support app-crypt/pinentry password input backend.

app-crypt

aespipe

asm	Enable assembly modules
cpu_flags_x86_padlock	Use VIA padlock instructions, detected at run time, code still works on non-padlock processors

ccid

kobil-midentity	Build and install Kobil_mIDentity_switch tool
twinserial	Enable twinserial reader

codecrypt

cryptopp	Build algorithms that need Crypto++ support dev-libs/crypto++

dehydrated

cron	Install cron job to sign/renew non-existent/changed/expiring certificates

eid-mw

dialogs	Enable "askaccess" dialog box, by using x11-libs/gtk+
gtk	All dialogs are available, by using x11-libs/gtk+
p11-kit	Support for app-crypt/p11-kit.
p11v220	Enable PKCS#11 v2.20 features.

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

smartcard	Build scdaemon software. Enables usage of OpenPGP cards. For other type of smartcards, try app-crypt/gnupg-pkcs11-scd. Bring in dev-libs/libusb as a dependency; enable scdaemon.
tofu	Enable support for Trust on First use trust model; requires dev-db/sqlite.
tools	Install extra tools (including gpgsplit and gpg-zip).
usb	Build direct CCID access for scdaemon; requires dev-libs/libusb.
user-socket	try a socket directory which is not removed by init manager at session end
wks-server	Install the wks-server

gnupg-pkcs11-scd

proxy	Build the gnupg-pkcs11-scd-prox

gpgme

common-lisp	Install common-lisp files

hashcat

brain	Enable the hashcat brain

heimdal

hdb-ldap	Adds support for LDAP as a database backend
lmdb	Add support for using dev-db/lmdb for lookup tables
otp	Adds support for one-time passwords
pkinit	Adds support for PKINIT for the initial ticket

hmaccalc

fips	Enable NSS FIPS mode and support only the FIPS-compliant functions

johntheripper-jumbo

opencl	Build with opencl/GPU cracking support
pcap	Build with pcap support

kbfs

git	Build the Git remote helper for storing repositories in Keybase

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.

libb2

native-cflags	Use CFLAGS as determined by configure script. These flags will enable all CPU specific features it find available, to further optimise the implementation. This discards any existing CFLAGS set in make.conf or similar.

libu2f-host

systemd	Use user ACLs rather than plugdev group to give user access to the HIDRAW device.

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
lmdb	Add support for using dev-db/lmdb for lookup tables
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

p11-kit

asn1	Enable ASN.1 certificate support
trust	Build the trust policy module

qca

botan	Enable botan plugin
gcrypt	Enable gcrypt plugin
gpg	Enable GnuPG plugin
logger	Enable logger plugin
nss	Enable NSS plugin
pkcs11	Enable PKCS#11 plugin
sasl	Enable SASL plugin
softstore	Enable softstore plugin

seahorse

ldap	Enable seahorse to manipulate GPG keys on a LDAP server.

swtpm

fuse	Support sys-fs/fuse based /dev/tpm interface

tpm-emulator

mtm-emulator	Build the MTM emulator

tpm-tools

pkcs11	Build Token data management utilities based on OpenCryptoki's (dev-libs/opencryptoki) PKCS#11 implementation.

tpm2-tools

fapi	Enable feature API tools

tpm2-tss

fapi	Enable feature API (requires openssl as crypto backend)
gcrypt	Use dev-libs/libgcrypt as crypto engine
openssl	Use dev-libs/openssl as crypto engine

veracrypt

asm	Enable assembly for optimization

zulucrypt

gnome	Enable support for the freedesktop.org Secret Service API via app-crypt/libsecret
kwallet	Enable encrypted storage of passwords with kde-frameworks/kwallet
udev	Whether udev will be consulted when deciding if a volume is system or not

app-dicts

aspell-be

classic	Support classic spelling by default

gwaei

hunspell	Enable app-text/hunspell spellchecking and morphological analysis
mecab	Enable app-text/mecab support

myspell-pt

preao	Use the pre ortographic agreement version of the dictionary

app-doc

clsync-docs

api	Install doxygen generated API docs.

csound-manual

html	Install HTML documentation

devmanual

offline	Use alternative minimal stylesheet instead of Tyrian theme

doxygen

clang	support for sys-devel/clang assisted parsing
dot	allow to create dot graphs using media-gfx/graphviz
doxysearch	build doxyindexer and doxysearch.cgi

kicad-doc

html	Generate documentation in HTML format
pdf	Generate documentation in PDF format

linuxfromscratch

htmlsingle	Install all-on-one-page HTML version.

pms

html	Generate and install PMS as .html as well
twoside	Enable two-sided layout suitable for printing

pms-bin

html	Install PMS as .html as well

tldp-howto

html	Install multi-chapter HTML docs
htmlsingle	Install all-on-one-page HTML docs
pdf	Install pdf docs
text	Install plain-text docs

app-editors

bluefish

gtk3	Enable GTK3 interface (default)
gucharmap	Enable gucharmap dictionary plugin
python	Enable Python integration for zen-coding plugin
spell	Enable spell checking capabilities via enchant library

emacs

athena	Enable the MIT Athena widget set (x11-libs/libXaw)
dynamic-loading	Enable loading of dynamic libraries at runtime
games	Support shared score files for games
gconf	Use gnome-base/gconf to read the system font name
gfile	Use gfile (dev-libs/glib) for file notification
gsettings	Use gsettings (dev-libs/glib) to read the system font name
gtk2	Prefer version 2 of the GIMP Toolkit to version 3 (x11-libs/gtk+)
gzip-el	Compress bundled Emacs Lisp source
harfbuzz	Use media-libs/harfbuzz as text shaping engine
imagemagick	Use media-gfx/imagemagick for image processing
json	Compile with native JSON support using dev-libs/jansson
libxml2	Use dev-libs/libxml2 to parse XML instead of the internal Lisp implementations
mailutils	Retrieve e-mail using net-mail/mailutils instead of the internal movemail substitute
source	Install C source files and make them available for find-function
threads	Add elisp threading support
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.
xwidgets	Enable use of GTK widgets in Emacs buffers (requires GTK3)

fe

sendmail	Send mail after editor abend

gedit-plugins

charmap	Insert special characters just by clicking on them
git	Shows document changes related to git's HEAD
terminal	Embed a terminal in the bottom pane

gnome-latex

latexmk	Install dev-tex/latexmk (used by default for the build tools)
rubber	Install dev-tex/rubber (can be used for the build tools)

gvim

cscope	Enable cscope interface
gtk2	Enable GTK+2 interface
netbeans	Include netbeans external editor integration support
racket	Enable support for Scheme using dev-scheme/racket

jasspa-microemacs

nanoemacs	Build NanoEmacs instead of MicroEmacs

joe

xterm	Enable full xterm clipboard support

leafpad

emacs	Enable Emacs key theme

mousepad

gtk3	Use GTK+3 instead of GTK+2

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.
magic	Add magic file support (sys-apps/file) to automatically detect appropriate syntax highlighting
minimal	Disable all fancy features, including ones that otherwise have a dedicated USE flag (such as spelling).
split-usr	Enable this if /bin and /usr/bin are separate directories

ne

tinfo	Link against libtinfo from sys-libs/ncurses

neovim

nvimpager	Install nvimpager symlink to less.sh macro
tui	Build the neovim unix tui

okteta

designer	Build plugins for dev-qt/designer

qhexedit2

gui	Install Qt5 hex editor

tea

aspell	Enable spellchecking using app-text/aspell
hunspell	Enable spellchecking using app-text/hunspell
qml	Enable support for plugins using QML

vim

X	Link console vim against X11 libraries to enable title and clipboard features in xterm
cscope	Enable cscope interface
racket	Enable support for Scheme using dev-scheme/racket
terminal	Enable terminal emulation support
vim-pager	Install vimpager and vimmanpager links

vis

tre	more memory efficient regex search using dev-libs/tre

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
mule	Add multi-language support to XEmacs
pop	Support POP for mail retrieval
xim	Enable X11 XiM input method

zile

valgrind	Enable usage of dev-util/valgrind in tests

app-emacs

auctex

preview-latex	Use bundled preview-latex

bbdb

tex	Install plain TeX support files
vm	Add support for app-emacs/vm

calfw

howm	Add support for the app-emacs/howm note-taking tool

elscreen

wanderlust	Include support for app-emacs/wanderlust

emacs-common-gentoo

games	Support shared score files for games

emacs-w3m

gzip-el	Compress bundled Emacs Lisp source

mu-cite

bbdb	Include support for app-emacs/bbdb

org-mode

contrib	Install user-contributed files
odt-schema	Install non-free schema files for OpenDocument Text exporter

remember

bbdb	Include support for app-emacs/bbdb
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

aranym

clipboard	Enable bidirectional clipboard transfer between the host and FreeMiNT
jit	Build Just-In-Time compiler variant with increased performance
lilo	Enable support for directly booting kernels such as Linux
osmesa	Allow images to be rendered in memory using the host CPU
pmmu	Build full PMMU variant, required for running mainline Linux
standard	Build standard (no JIT or PMMU) variant

bochs

3dnow	Enable support for emulating 3DNow! instructions (incomplete)
avx	Enable support for emulating Advanced Vector Extensions (AVX)
debugger	Enable debugger (slows down emulation)
gdb	Enable support for the remote GDB stub
x86-64	Enable support for emulation of 64-bit CPUs

containerd

apparmor	Support for AppArmor
btrfs	Support for BTRFS snapshot driver
cri	Support for Kubernetes CRI

containers-storage

btrfs	Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.
device-mapper	Enables dependencies for the "devicemapper" graph driver, including necessary kernel flags.

cri-o

btrfs	Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.
device-mapper	Enables dependencies for the "devicemapper" graph driver, including necessary kernel flags.
ostree	Enables dependencies for handling of OSTree images.

crossover-bin

capi	Enable ISDN support via CAPI
opencl	Enable OpenCL support
osmesa	Add support for OpenGL in bitmaps using libOSMesa
pcap	Support packet capture software (e.g. wireshark)
vulkan	Enable Vulkan drivers

crun

bpf	Enable in Kernel, eBPF (enhanced Berkley Packet Filter) support for managing device controllers.

docker

apparmor	Enable AppArmor support.
aufs	Enables dependencies for the "aufs" graph driver, including necessary kernel flags.
btrfs	Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.
container-init	Makes the a staticly-linked init system tini available inside a container.
device-mapper	Enables dependencies for the "devicemapper" graph driver, including necessary kernel flags.
overlay	Enables dependencies for the "overlay" graph driver, including necessary kernel flags.

docker-credential-helpers

gnome-keyring	Build secretservice helper which works with gnome-keyring or kwallet using D-Bus.
pass	Build pass helper for the pass utility.

dosemu

fluidsynth	use media-sound/fluidsynth for MIDI emulation

faudio

dumpvoices	FAudio dumps buffer data to individual files with RIFF/XWMA headers, usable with players like ffplay/testxwma.
ffmpeg	FAudio has optional support for decoding xWMA resources using FFmpeg, requiring: media-video/ffmpeg (note: this feature is not supported by media-video/libav).
test	Build and run faudio testsuite.
utils	Build all faudio utilities.
xnasong	Build support for optional XNG_SONG component (note: this not required by app-emulation/wine-staging, app-emulation/wine-vanilla for faudio XAudio support).

fs-uae

fmv	Enable support for CD32 FMV (full motion video)
glew	Enable support for The OpenGL Extension Wrangler Library (media-libs/glew)

fs-uae-launcher

lha	Enable LHA archive support

fuse

backend-X	Use X11 rendering backend
backend-fbcon	Use framebuffer rendering backend
backend-sdl	Use SDL rendering backend
backend-svga	Use svgalib rendering backend
memlimit	Add compile-time memory usage limiting

fuse-utils

gcrypt	Use dev-libs/libgcrypt for low-level crypto of some features, including logfiles.

ganeti

drbd	Enable DRBD support
experimental	Enable experimental patches. Warning! This will break RPC within major versions if the patches applied differ!
haskell-daemons	Build haskell daemons instead of python
htools	Enable htools support
kvm	Enable KVM support
lxc	Enable Linux Countainers support
monitoring	Enable the ganeti monitoring daemon
multiple-users	Enable support for running VMs as different users
rbd	Enable rados block device support via sys-cluster/ceph
restricted-commands	Enable restricted commands in the node daemon
xen	Enable Xen support

hyperd

libvirt	Enable support for KVM via libvirt
xen	Enable support for the Xen Hypervisor

libcacard

passthrough	Enable smartcard passthrough support via sys-apps/pcsc-lite

libguestfs

erlang	Build Erlang bindings
fuse	Enable image mount support via fuse
inspect-icons	Use media-gfx/icoutils for acces icon file in image and inspect it
libvirt	Use app-emulation/libvirt to manipulate VMs
systemtap	Use dev-util/systemtap to inspect VM via "probes" way

libpod

apparmor	Enable AppArmor support.
btrfs	Enables dependencies for the "btrfs" graph driver, including necessary kernel flags.
fuse	Enables fuse dependencies (fuse-overlayfs is especially useful for rootless mode).
rootless	Enables dependencies for running in rootless mode.

libspectrum

gcrypt	Use dev-libs/libgcrypt for low-level crypto of some features, including logfiles.

libvirt

apparmor	Enable AppArmor support
dtrace	Enable dtrace support via dev-util/systemtap
firewalld	DBus interface to iptables/ebtables allowing for better runtime management of your firewall.
fuse	Allow LXC to use sys-fs/fuse for mount points
glusterfs	Enable GlusterFS support via sys-cluster/glusterfs
iscsi	Allow using an iSCSI remote storage server as pool for disk image storage
iscsi-direct	Allow using libiscsi for iSCSI storage pool backend
libssh	Use net-libs/libssh to communicate with remote libvirtd hosts, for example: qemu+libssh://server/system
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-fs/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.
nfs	Allow using Network File System mounts as pool for disk image storage
numa	Use NUMA for memory segmenting via sys-process/numactl and sys-process/numad
openvz	Support management of OpenVZ virtualisation (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 IBM HMC / IVM hypervisor via PHYP protocol
qemu	Support management of QEMU virtualisation (app-emulation/qemu)
rbd	Enable rados block device support via sys-cluster/ceph
vepa	Virtual Ethernet Port Aggregator (VEPA) / 802.1Qbg support. Relies on macvtap support.
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-bin)
wireshark-plugins	Build the net-analyzer/wireshark plugin for the Libvirt RPC protocol
xen	Support management of Xen virtualisation (app-emulation/xen)
zfs	Enable ZFS backend storage sys-fs/zfs

lxc

apparmor	Enable AppArmor support
templates	Install old style templates through app-emulation/lxc-templates
tools	Build and install additional command line tools

lxd

daemon	Build the system daemon, not just the client tool
dnsmasq	Depend on dnsmasq to provide DHCP and DNS
tools	Build and install optional tools

nemu

network-map	Adds possibility of exporting network map to SVG
ovf	Adds support for OVA/OVF import
savevm	Adds support for QEMU savevm snapshots (experimental, QEMU must be patched)
spice	Adds Spice protocol support
vnc-client	Adds support for external VNC client

open-vm-tools

deploypkg	Build deploypkg plugin
dnet	Enable support for nicinfo
doc	Generate API documentation
fuse	Enable vmblock-fuse/vmhgfs-fuse
gtkmm	Compile with Gtkmm and sigc++ (Recommended)
multimon	Enable multimon (Requires X)
resolutionkms	Build the linux/unix resolutionkms module
vgauth	Build vgauth

pcem

networking	Enable support for emulation of network cards.

playonlinux

winbind	Enables support for the winbind auth daemon

punes

cg	Add support for Nvidia CG Toolkit

q4wine

ico	Enable ico support via media-gfx/icoutils
iso	Support unprivileged mounting of ISO9660 images via sys-fs/fuseiso
wineappdb	Enable Wine AppDB browser support

qemu

accessibility	Adds support for braille displays using brltty
aio	Enables support for Linux's Async IO
alsa	Enable alsa output for sound emulation
capstone	Enable disassembly support with dev-libs/capstone
curl	Support ISOs / -cdrom directives vis HTTP or HTTPS.
fdt	Enables firmware device tree support
glusterfs	Enables GlusterFS cluster fileystem via sys-cluster/glusterfs
gnutls	Enable TLS support for the VNC console server. For 1.4 and newer this also enables WebSocket support. For 2.0 through 2.3 also enables disk quorum support.
io-uring	Enable efficient I/O via sys-libs/liburing.
iscsi	Enable direct iSCSI support via net-libs/libiscsi instead of indirectly via the Linux block layer that sys-block/open-iscsi does.
jemalloc	Enable jemalloc allocator support
jpeg	Enable jpeg image support for the VNC console server
ncurses	Enable the ncurses-based console
nfs	Enable NFS support
numa	Enable NUMA support
pin-upstream-blobs	Pin the versions of BIOS firmware to the version included in the upstream release. This is needed to sanely support migration/suspend/resume/snapshotting/etc... of instances. When the blobs are different, random corruption/bugs/crashes/etc... may be observed.
plugins	Enable qemu plugin API via shared library loading.
png	Enable png image support for the VNC console server
pulseaudio	Enable pulseaudio output for sound emulation
rbd	Enable rados block device backend support, see http://ceph.newdream.net/wiki/QEMU-RBD
sdl	Enable the SDL-based console
sdl-image	SDL Image support for icons
spice	Enable Spice protocol support via app-emulation/spice
ssh	Enable SSH based block device support via net-libs/libssh2
static	Build the User and Software MMU (system) targets as well as tools as static binaries
static-user	Build the User targets as static binaries
systemtap	Enable SystemTAP/DTrace tracing
tci	Enable the TCG Interpreter which can speed up or slowdown workloads depending on the host and guest CPUs being emulated. In the future it will be a runtime option but for now its compile time.
usb	Enable USB passthrough via dev-libs/libusb
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
vhost-user-fs	Enable shared file system access using the FUSE protocol carried over virtio.
virgl	Enable experimental Virgil 3d (virtual software GPU)
virtfs	Enable VirtFS via virtio-9p-pci / fsdev. See http://wiki.qemu.org/Documentation/9psetup
vte	Enable terminal support (x11-libs/vte) in the GTK+ interface
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 xfsctl() notification and syncing for XFS backed virtual disks.
xkb	Depend on x11-libs/libxkbcommon to build qemu-keymap tool for converting xkb keymaps

qt-virt-manager

smartcard	Enable smartcard remoting using app-emulation/libcacard

runc

ambient	Enable support for ambient capabilities set (Requires Linux kernel 4.3 or later).
apparmor	Enable AppArmor support.
kmem	Enable Kernel Memory Accounting.

runv

libvirt	Enable support for KVM via libvirt
xen	Enable support for the Xen Hypervisor

ski

debug	enable extra binary emulation debugging via sys-libs/binutils-libs

skopeo

btrfs	Enables dependencies for the "btrfs" graph driver.

spice

smartcard	Enable smartcard remoting using app-emulation/libcacard

spice-vdagent

consolekit	Use sys-auth/consolekit to determine the master vdagentd in case of multiple running vdagentds (highly recommended)

vagrant

virtualbox	Use VirtualBox provider.

vice

ethernet	Enable ethernet emulation
headless	Include the headless variant of the emulator
mpg123	Enable mp3@64 cartridge support
parport	Enable parallel port SID support
pci	Enable PCI device discovery using sys-apps/pciutils

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).

virt-viewer

libvirt	Support connecting to virtual machines managed by libvirt.
spice	Support connecting to SPICE-enabled virtual machines.
vnc	Support connecting to VNC-enabled virtual machines.

virt-what

dmi	Use sys-apps/dmidecode to read firmware data

virtualbox

dtrace	Install dtrace Extension Pack
headless	Build without any graphic frontend
lvm	Build VBoxVolInfo that needs devicemapper from sys-fs/lvm2.
pax_kernel	Apply patch needed for pax enabled kernels.
sdk	Enable building of SDK
udev	Controls installation of special USB udev rules.
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

vkd3d

spirv-tools	Enable SPIRV shader debugging support using dev-util/spirv-tools

wine-staging

capi	Enable ISDN support via CAPI
custom-cflags	Bypass strip-flags; use at your own peril
dos	Pull in games-emulation/dosbox to run DOS applications
faudio	Pull in app-emulation/faudio to provide XAudio2 functionality
gcrypt	Add support for the Diffie-Hellman key exchanges using dev-libs/libgcrypt
gecko	Add support for the Gecko engine when using iexplore
gssapi	Use GSSAPI (Kerberos SSP support)
gstreamer	Use media-libs/gstreamer to provide DirectShow functionality;
mono	Add support for .NET using Wine's Mono add-on
netapi	Use libnetapi from net-fs/samba to support Windows networks in netapi32.dll
opencl	Enable OpenCL support
osmesa	Add support for OpenGL in bitmaps using libOSMesa
pcap	Support packet capture software (e.g. wireshark)
perl	Install helpers written in perl (winedump/winemaker)
pipelight	Apply Wine-Staging patches for Pipelight/Silverlight support
prelink	Run prelink on DLLs during build; For Gentoo hardened, do not disable if you do not know what this means as it can break things at runtime
realtime	Pull in sys-auth/rtkit for low-latency pulseaudio support
run-exes	Use Wine to open and run .EXE and .MSI files
samba	Add support for NTLM auth. See: https://web.archive.org/web/20160108123008/http://wiki.winehq.org:80/NtlmAuthSetupGuide and https://web.archive.org/web/20150906013746/http://wiki.winehq.org/NtlmSigningAndSealing (these pages are not currently in the updated WineHQ Wiki).
sdl	Add support for gamepad detection using SDL
staging	Apply Wine-Staging patches for advanced feature support that haven't made it into upstream Wine yet
themes	Support GTK+:3 window theming through Wine-Staging
udev	Use virtual/libudev to provide plug and play support
unwind	Use sys-libs/libunwind to unwind the stack
vkd3d	Use app-emulation/vkd3d to provide Direct3D 12 support
vulkan	Enable Vulkan drivers

wine-vanilla

capi	Enable ISDN support via CAPI
custom-cflags	Bypass strip-flags; use at your own peril
dos	Pull in games-emulation/dosbox to run DOS applications
faudio	Pull in app-emulation/faudio to provide XAudio2 functionality
gecko	Add support for the Gecko engine when using iexplore
gssapi	Use GSSAPI (Kerberos SSP support)
gstreamer	Use media-libs/gstreamer to provide DirectShow functionality;
mono	Add support for .NET using Wine's Mono add-on
netapi	Use libnetapi from net-fs/samba to support Windows networks in netapi32.dll
opencl	Enable OpenCL support
osmesa	Add support for OpenGL in bitmaps using libOSMesa
pcap	Support packet capture software (e.g. wireshark)
perl	Install helpers written in perl (winedump/winemaker)
prelink	Run prelink on DLLs during build; For Gentoo hardened, do not disable if you do not know what this means as it can break things at runtime
realtime	Pull in sys-auth/rtkit for low-latency pulseaudio support
run-exes	Use Wine to open and run .EXE and .MSI files
samba	Add support for NTLM auth. See: https://web.archive.org/web/20160108123008/http://wiki.winehq.org:80/NtlmAuthSetupGuide and https://web.archive.org/web/20150906013746/http://wiki.winehq.org/NtlmSigningAndSealing (these pages are not currently in the updated WineHQ Wiki).
sdl	Add support for gamepad detection using SDL
udev	Use virtual/libudev to provide plug and play support
unwind	Use sys-libs/libunwind to unwind the stack
vkd3d	Use app-emulation/vkd3d to provide Direct3D 12 support
vulkan	Enable Vulkan drivers

winetricks

rar	Pull in app-arch/unrar for extraction of rar-compressed game files

x48

readline	Enables support for libreadline

xe-guest-utilities

xenstore	Use xenstore binaries bundled by Citrix instead of building app-emulation/xen-tools

xen

efi	Adds efi boot support, requires LDFLAG -melf_x86_64 for amd64
flask	Enable the Flask XSM module from NSA

xen-tools

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)
ipxe	Enable ipxe support
ocaml	Enable support for the ocaml language
ovmf	Enable support to boot UEFI guest vm, needed by hvm
pygrub	Install the pygrub boot loader
qemu	Enable IOEMU support via the use of qemu-dm
qemu-traditional	Build the old qemu traditional device model (useful only if you cannot change to the new device model e.g. Windows VMs)
rombios	Enable rombios support, needed by ipxe
screen	Enable support for running domain U console in an app-misc/screen session
system-ipxe	Using sys-firmware/ipxe instead of the bundled one
system-qemu	Using app-emulation/qemu instead of the bundled one
system-seabios	Using sys-firmware/seabios instead of the bundled one

xtrs

ls-dos	Install LS-DOS disk images for Model 4P

app-eselect

eselect-php

fpm	Enable the FastCGI Process Manager SAPI

app-forensics

afflib

fuse	Enable extra fuse thingies
qemu	Enable qemu stuff
s3	Enable support for Amazon S3

aide

e2fs	Enable support for checking file attributes on ext2/ext3/ext4 filesystems
prelink	Bypass prelinking when calculating checksums

chkrootkit

cron	Install cron script for weekly rootkit scans

libewf

bfio	Enables libbfio for chaining file in file handling
fuse	Enable fuse support for ewfmount
uuid	Enable UUID support in the ewftools

openscap

gconf	Build the gconf independant probes
nss	Prefer NSS over libgcrypt as the crypto engine
rpm	Compiles the RPM probes
sce	Enables Script Check Engine (SCE) support
sql	Build the sql independant probes

quickfuzz

archs	support archive formats
codes	support cource code formats
docs	support document formats
imgs	support image formats
media	support media formats
net	support networking formats
pki	support PKI formats

sleuthkit

aff	Enable extra aff formats
ewf	Enable libewf support

app-i18n

anthy

canna-2ch	Enable support for app-dicts/canna-2ch

canna

canuum	Build canuum

fcitx

autostart	Enable XDG-compatible autostart of Fcitx
enchant	Enable Enchant backend (using app-text/enchant) for spelling hinting
gtk2	Install input method module for GTK+ 2
gtk3	Install input method module for GTK+ 3
opencc	Enable OpenCC engine (using app-i18n/opencc) for converter between Simplified Chinese and Traditional Chinese
pango	Enable support for x11-libs/pango
table	Install table input methods for Simplified Chinese

fcitx-libpinyin

dictionary-manager	Install dictionary manager

fcitx-rime

configuration_tool	Install configuration tool

fcitx-unikey

macro-editor	Install macro editor

freewnn

uum	Build uum

ibus

emoji	Enable support for Emoji
gconf	Enable support for gnome-base/gconf
gtk2	Enable support for x11-libs/gtk+:2
unicode	Enable support for Unicode choice

ibus-chewing

gconf	Enable support for gnome-base/gconf

ibus-handwrite

zinnia	Enable support for app-i18n/zinnia

ibus-libpinyin

boost	Compile against dev-libs/boost libraries
opencc	Enable support for app-i18n/opencc

ibus-m17n

gtk2	Build with x11-libs/gtk+:2 instead of x11-libs/gtk+:3

ibus-pinyin

boost	Enable support for dev-libs/boost

ibus-unikey

gtk2	Enable support for x11-libs/gtk+:2

im-chooser

gtk2	Build with x11-libs/gtk+:2 instead of x11-libs/gtk+:3
xfce	Enable support for XFCE panel

imsettings

gconf	Enable support for gnome-base/gconf
gtk2	Build with x11-libs/gtk+:2 instead of x11-libs/gtk+:3
xfconf	Enable support for xfce-base/xfconf

librime

debug	Enable debugging (including logging of input of RIME input methods)

mozc

fcitx4	Enable support for app-i18n/fcitx 4
gui	Install graphical user interface tool (mozc_tool)
handwriting-tegaki	Use handwriting recognition model from app-i18n/tegaki-zinnia-japanese by default
handwriting-tomoe	Use handwriting recognition model from app-i18n/zinnia-tomoe by default
ibus	Enable support for app-i18n/ibus
renderer	Enable native candidate window

pyzy

boost	Enable support for dev-libs/boost
doc	Generate API documentation
opencc	Enable support for app-i18n/opencc

rime-data

extra	Install extra packages

scim

gtk3	Enable support for x11-libs/gtk+:3

scim-anthy

gtk3	Enable support for x11-libs/gtk+:3
kasumi	Use Anthy dictionary maintenance tool (app-dicts/kasumi)

scim-sunpinyin

gtk3	Enable support for x11-libs/gtk+:3

tomoe

hyperestraier	Enable support for app-text/hyperestraier

translate-shell

tts	Enable text-to-speech support

uim

anthy	Enable support for app-i18n/anthy
eb	Enable support for dev-libs/eb
gtk2	Enable support for x11-libs/gtk+:2
skk	Enable support for app-i18n/skk-jisyo

app-laptop

hdapsd

libconfig	Require dev-libs/libconfig to allow the daemon to read a configuration file at startup

ibam

gkrellm	Enable building of app-admin/gkrellm module

laptop-mode-tools

apm	Add APM (Advanced Power Management) support

pbbuttonsd

ibam	Enable support for Intelligent Battery Monitoring
macbook	Enable support for the Macbook and Macbook Pro

thinkfan

atasmart	include libatasmart support to get disc temperature
nvidia	allow thinkfan to read GPU temperature from the proprietary nVidia driver
yaml	use YAML format for config file

tp_smapi

hdaps	Install a compatible HDAPS module

app-leechcraft

lc-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
birthdaynotifier	Build Birthday Notifier for you to not forget about birthdays of your contacts.
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
keeso	Build plugin for changing text into SoMEtHInG lIKe THiS
lastseen	Build plugin for client-side recording of the last online/available time
media	Enable media calls
metacontacts	Build plugin for metacontacts support
murm	Build Murm, the VKontakte messaging support via their native API (instead of XMPP)
nativeemoticons	Build support for native Azoth's emoticons packs
otroid	Build OTRoid, plugin for the Off-the-Record deniable encryption system
sarin	Build Sarin, Tox protocol support module. Please add mva overlay to use net-libs/tox
shx	Build shell command executor plugin
standardstyles	Build support for standard Azoth styles engine
vader	Bulid Vader, the MRIM (Mail.Ru Agent) protocol support plugin
velvetbird	Build support for protocols provided by libpurple
woodpecker	Build Woodpecker, the Twitter client plugin
xtazy	Build Xtazy for publishing currently playing tune

lc-blasq

deathnote	Support LiveJournal FotoBilder service
rappor	Support VKontakte service
spegnersi	Support Flickr service
vangog	Support Picasa service

lc-blogique

hestia	Allows one to keep a local blog
metida	Support for the LiveJournal blogging platform

lc-core

qwt	Support for QML plotting item through x11-libs/qwt

lc-gmailnotifier

notify	Pull in a plugin to show notifications from GMail Notiifer
quark	Pull in a plugin to show GMail Notifier's quark

lc-liznoo

battery	Enables battery charge level reading support.
poweractions	Enables support for suspending and hibernating the machine.
powerevents	Enables support for receiving events about suspending and resuming the machine (to notify other plugins).

lc-lmp

fradj	Build FrAdj, the equalizer effect module
graffiti	Build media tags editor plugin
mp3tunes	Build plugin for supporting the mp3tunes.com music locker service
mpris	Enable MPRIS support
potorchu	Enable the projectM-based visualization effects module for LMP

lc-monocle

fb2	Enable support for FictionBook format
mobi	Enable support for MOBI format

lc-musiczombie

acoustid	Use media-libs/chromaprint for acoustic fingerprinting

lc-netstoremanager

dropbox	Build Dropbox storage backend
googledrive	Build Google Drive storage backend

lc-poshuku

autosearch	Provide automatic search suggestions for Poshuku.
cleanweb	Build CleanWeb for ad blocking compatible with Firefox's AdBlock+.
dcac	Build color inverter module providing a night mode.
fatape	Build FatApe, GreaseMonkey userscripts support layer.
filescheme	Build FileScheme for accessing local URLs.
foc	Build FOC for Flash-on-Click functionality.
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.
qrd	Build module for displaying the QR code of a web page.
speeddial	Build SpeedDial module.
webengine	Build WebEngine- (that is, Chromium-)based rendering backend.

lc-secman

exposecontents	Build the GUI for viewing the stored data.

leechcraft-meta

de	Install components that allow using LeechCraft as Desktop Environment

app-metrics

collectd

contrib	Install user-contributed files in the doc directory
filecaps	When set collectd daemon will have set required capabilities to run most plugins even if run as unprivileged user
java	Must be set (workaround for java-pkg-opt-2 eclass limitation) when you want java or genericjmx plugin
udev	Enable optional udev usage in disk plugin; Required for smart plugin
xfs	Enable optional capability to filter on XFS file system in df plugin; Requires XFS headers from sys-fs/xfsprogs

app-misc

anki

recording	Enable support for audio recording
sound	Enable support for adding sound to cards

binwalk

graph	Enable support for generating entropy graphs

blink1

mini-tool	Build and install command-line mini-tool blink1-mini-tool (normally used for embedded devices)
server	Build and install REST API server (currently hard-coded to TCP port 8080)
tool	Build and install command-line tool blink1-tool

byobu

screen	Use app-misc/screen as the default backend

ca-certificates

cacert	Include root certificates from CAcert (http://www.cacert.org/) and Software in the Public Interest (http://www.spi-inc.org/)

carbon-c-relay

lz4	add support for LZ4 compressed transport
oniguruma	use dev-libs/oniguruma as regex implementation
pcre2	use dev-libs/libpcre2 as regex implementation
snappy	add support for Snappy compressed transport

ddccontrol

pci	enable direct PCI memory access (the setuid ddcpci util)

ddcutil

drm	Use x11-libs/libdrm for more verbose diagnostics.
usb-monitor	Adds support for monitors attached via USB.
user-permissions	Adds a udev rules to allow non-root users in the i2c group to access the /dev/i2c-* devices. If usb-monitor is selected, users will need to be added to the video group to access the USB monitor. Otherwise, only root will be able to use ddcutil.

digitemp

ds2490	Build support for the ds2490 sensor
ds9097	Build support for the ds9097 sensor
ds9097u	Build support for the ds9097u sensor

elasticsearch

x-pack	Enable additional features (may need a license)

emelfm2

ansi	Add support for ANSI escape sequences
gtk3	Use x11-libs/gtk+:3 instead of x11-libs/gtk+:2

g810-led

hidapi	Use dev-libs/hidapi instead of virtual/libusb for talking to the device (advertised to be faster)

gcstar

stats	Enable statistics reporting
tellico	Enable support for kde-misc/tellico files

geoclue

modemmanager	Enable geolocation through 3G or GPS enabled hardware through net-misc/modemmanager.
zeroconf	Enable retrieval of GPS location from Android devices with https://wiki.gnome.org/Apps/GeoclueShare

gramps

geo	Enable rendering of geographical data using sci-geosciences/osm-gps-map
rcs	Adds support for family tree archives via dev-vcs/rcs
reports	All external software that is needed for graphical reports will be installed

graphlcd-base

fontconfig	Add support for media-libs/fontconfig font names.
freetype	Add support for media-libs/freetype.
g15	Add support for app-misc/g15daemon, used by the Logitech G15 keyboard.
graphicsmagick	Add support for media-gfx/graphicsmagick.
imagemagick	Add support for media-gfx/imagemagick.

irtrans-irserver

mono	Enable mono support

jq

oniguruma	Use dev-libs/oniguruma for regular expression support

kryoflux-dtc

demos	Install example floppy game files.
fast-firmware	Install fast firmware instead of slow firmware.

lcd4linux

apm	Enable the APM plugin.
asterisk	Enable the Asterisk plugin.
button-exec	Enable the Button plugin, to execute something on keypress.
cpuinfo	Enable the cpuinfo plugin.
dbus	Enable the dbus plugin.
diskstats	Enable the diskstats plugin.
dmalloc	Enable dmalloc for debugging.
dvb	Enable support for the DVB plugin.
event	Enable the event plugin.
exec	Enable the exec plugin, to read output from external programs.
fifo	Enable the FIFO (First-In, First-Out) plugin.
file	Enable the file plugin, to read from input from files.
gps	Enable the gps plugin, for reading gps coordinates.
hddtemp	Enable the hddtemp plugin, to read from the hddtemp daemon.
huawei	Enable the huawei plugin, to read from a huawei device.
i2c-sensors	Enable the i2c_sensors plugin, to read sensor data.
iconv	Enable the iconv plugin, to convert between encodings.
isdn	Enable the isdn plugin, to get information about ISDN.
kvv	Enable the kvv plugin, to get realtime train schedule from the Karlsruher Verkehrsverbund.
loadavg	Enable the loadavg plugin, to get stats load
meminfo	Enable the meminfo plugin, to get memory statistics.
mpd	Enable the mpd plugin, to read from the Music Player Daemon.
mpris-dbus	Enable the mpris plugin, to read data via dbus for mpris.
mysql	Enable the mysql plugin, to get mysql database information.
netdev	Enable the netdev plugin, to get interface statistics.
netinfo	Enable the netinfo plugin, to get more interface statistic.
outb	Enable raw i/o access.
pop3	Enable the pop3 plugin, to get notified about new mails.
proc-stat	Enable the proc_stat plugin, to read data from the proc file system.
python	Enable support for dev-lang/python and enable the python plugin, to execute own python scripts.
qnaplog	Enable the qnaplog plugin, to read a log from a QNAP device.
raspi	Enable the raspi plugin, to read sensor data from a Raspberry Pi.
sample	Enable the sample plugin.
statfs	Enable the statfs plugin, to get statistics about the file system.
uname	Enable the uname plugin, to get the output of uname.
uptime	Enable the uptime plugin.
w1retap	Enable the w1retap plugin.
wireless	Enable the wireless plugin, to get wireless statistics.

lcdproc

ethlcd	Enable support for ethlcd in the hd44780 driver.
extra-charmaps	Enable extra language specific charmaps.
freetype	Enable support for media-libs/freetype in the glcd driver.
menu	Enable menu support in the lcdproc client.
nfs	Display NFS filesystem stats in the lcdproc client.
png	Enable support for media-libs/libpng in the glcd driver.
samba	Display SMBFS filesystem stats in the lcdproc client.
test-menu	Enable test menu support for the lcdproc server.

lirc

audio	Support using an audio device connected to an IR receiver
devinput	Support the devinput input device
ftdi	Support FTDI devices
gtk	Include GTK support which enables the use of lirc-setup
inputlirc	Add a dependency on app-misc/inputlircd
uinput	Enable support for uinput

mc

edit	Compile and install the mcedit application
sftp	Add support for sftp (uses net-libs/libssh2 for it).
slang	Use sys-libs/slang instead of sys-libs/ncurses.
xdg	Toggles mc's config dir location. Enable for $XDG_CONFIG_HOME/mc, disable for $HOME/.mc

mosquitto

bridge	Enable bridge support in the MQTT broker.
persistence	Store messages and subscriptions to a file.
srv	Include SRV lookup support.
websockets	Support the WebSocket protocol.

muttprint

doc	Builds documentation

neofetch

X	Enable support for detecting DEs, WMs, screen resolutions, and showing images from an X terminal

note

general	Add support for ascii flatfile backend
text	Add support for text backend

pax-utils

python	Install a more powerful/faster version of lddtree

recoll

camelcase	Enable indexing for camelCase sentences and words
chm	Enable CHM file support via dev-python/pychm
inotify	Use the Linux Kernel notification subsystem for monitoring file alterations in realtime
session	Stop monitoring file alterations when X11 session terminates
webengine	Use dev-qt/qtwebengine for fancy result list display

rlwrap

debug	Enable debug

screen

multiuser	Enable multiuser support (by setting correct permissions)
nethack	Express error messages in nethack style

screenfetch

X	Use the media-gfx/scrot package to take screenshots

skim

tmux	Install sk-tmux script to run skim in a tmux pane
vim	Install vim plugin for skim

sphinx

id64	use 64-bit document and word IDs
mariadb	Add mariadb database support
re2	use the dev-libs/re2 regular expression library
stemmer	Enable language stemming support

task

sync	Enable "task sync" support

tmux

utempter	Include libutempter support

towitoko

moneyplex	Makes libtowitoko work for the moneyplex home banking software

tracker

miners	Install the app-misc/tracker-miners package for actual data mining support for tracker
stemmer	Add word stemming via dev-libs/snowball-stemmer.

tracker-miners

cue	Enable cue sheet parsing
gsf	Enable gnome-extra/libgsf based data extractor and for ODT.
iptc	Enable extraction of IPTC data from pictures
iso	Enable extraction of metadata from ISO disk images
playlist	Add support for playlists
xps	Add support for XPS file format through app-text/libgxps.

unfoo

minimal	Do not install all support archive binaries

vcontrold

man	Build the manpages
vclient	Build the vclient helper program to talk to vcontrold
vsim	Build the vsim helper program (simulates the heating's answers, for development and debugging)

vifm

developer	Enable features of interest to developers
extended-keys	Support for extended keys (arrows, home etc)
gtk	Use gtk+ to determine mimetypes
vim	Install the vifm vim plugin and vim-compatible documentation

worker

avfs	Enable support for sys-fs/avfs

workrave

mate	Add support for MATE panel
xfce	Add support for XFCE panel

zygrib

maps	Installs additional GSHHS maps for high resolution coastline data and cities

app-mobilephone

adb-sync

channel	Install the adb-channel script

gammu

bluetooth	Enables bluetooth support
curl	Enables curl support
irda	Enables infrared support
mysql	Use mysql for data storage
nls	Enable native language support
odbc	Use ODBC as DB connector
postgres	Use PostgreSQL for data storage
usb	Enable USB suport

gnokii

ical	Enable support for dev-libs/libical
irda	Enable infrared support
pcsc-lite	Enable smartcard support with sys-apps/pcsc-lite
sms	Enable SMS support (build smsd)

smstools

stats	Enable statistic reporting

app-office

abiword

collab	Enable collaborative editing plugin
goffice	Enable goffice plugin
grammar	Enable grammar checking via dev-libs/link-grammar
map	Enable world map support through media-libs/libchamplain
math	Enable support for x11-libs/gtkmathview
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.
redland	Enables support redland and raptor libs.
thesaurus	Enable thesaurus support
wordperfect	Enable wordperfect file support via app-text/libwpd

calligra

activities	Enable kactivities support
charts	Build chartshape plugin for creating business charts with dev-libs/kdiagram
gemini	Enable tablet and 2:1 devices support
import-filter	Enable support for various import filter file formats like WordPerfect, Visio and Apple Keynote
lcms	Build colorengine plugins using media-libs/lcms
okular	Enable bindings for kde-apps/okular
phonon	Build stage/eventplugins and videoshape plugin using media-libs/phonon
spacenav	Enable support for the 3Dconnexion spacenav input device via dev-libs/libspnav

calligraplan

activities	Enable kactivities support
holidays	Enable kde-frameworks/kholidays integration
kwallet	Enable access to encrypted OpenDocument files with kde-frameworks/kwallet storage

glabels

barcode	Enable barcode support through external libraries.

gnucash

aqbanking	Connect to some internet banks via AqBanking
quotes	Enable Online Stock Quote retrieval
register2	Use the new register (Experimental)

gnumeric

libgda	Enable database support through gnome-extra/libgda.
perl	Enable perl plugin loader.

grisbi

goffice	enable goffice graphic support

kexi

experimental	Enable features deemed experimental by upstream
marble	Enable displaying of maps using kde-apps/marble
mdb	Enable support for Microsoft Access database
webkit	Enable web form designer widget using dev-qt/qtwebkit

kmymoney

activities	Enable kde-frameworks/kactivities integration
addressbook	Enable kde-apps/akonadi contact integration
hbci	Enable HBCI support using net-libs/aqbanking
holidays	Enable kde-frameworks/kholidays integration
quotes	Enable Online Stock Quote retrieval
weboob	Enable import of online banking transactions extracted by www-client/weboob

kraft

pim	Enable support for KDE PIM resources integration

libreoffice

coinmp	Use sci-libs/coinor-mp as alternative solver
googledrive	Enable support for remote files on Google Drive
gtk2	Enable legacy gtk2 frontend
mariadb	Prefer mariadb connector over mysql connector
odk	Build the Office Development Kit
pdfimport	Enable PDF import via the Poppler library

libreoffice-l10n

offlinehelp	Install help files locally instead of using the LibreOffice Wiki

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.
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

magicpoint

contrib	Install additional contributed scripts

orage

clock-panel-plugin	Build the clock plugin for the XFCE panel

scribus

boost	Enable support for Boost based enhancement
hunspell	Enable support for spell checking with app-text/hunspell
minimal	Don't install headers (only required for e.g. plug-in developers)
osg	3D redering via dev-games/openscenegraph
scripts	Install the scripts
templates	Document tamplates
tk	Install tk based scripts e.g. FontSample.py

skrooge

activities	Enable kactivities support
designer	Build plugins for dev-qt/designer
webkit	Build with dev-qt/qtwebkit instead of dev-qt/qtwebengine

texmacs

netpbm	Add support for media-libs/netpbm

texstudio

video	Use phonon for video embedding

app-pda

barry

boost	Enable boost support
gui	Install the GUI backup tool

gtkpod

clutter	Enable clutter support for displaying coverart

app-portage

conf-update

colordiff	Use colors when displaying diffs (app-misc/colordiff)
libressl	Enable SSL connections and crypto functions using dev-libs/libressl

eix

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
sqlite	Compile in support for portage's sqlite backend; to actually use it you need additional configuration of portage and eix

g-sorcery

bson	Support BSON file format for package DB

gemato

gpg	Install dependencies needed for OpenPGP signature verification support
tools	Install additional utilities (benchmarks, hash testing tools, fast Manifest generators) to /usr/share/gemato.

grs

server	Install all the tools building systems

layman

cvs	Support dev-vcs/cvs based overlays
darcs	Support dev-vcs/darcs based overlays
g-sorcery	Support app-portage/g-sorcery based overlays
git	Support dev-vcs/git based overlays
gpg	Support app-crypt/gnupg signed overlays lists and manifests
mercurial	Support dev-vcs/mercurial based overlays
squashfs	Support mounting squashfs image overlays locally read-only
subversion	Support dev-vcs/subversion based overlays
sync-plugin-portage	Install the sys-apps/portage sync module

pfl

network-cron	Adds a cron job which does a weekly submit of the package database

portage-utils

qmanifest	Build qmanifest applet, this adds additional dependencies for GPG, OpenSSL and BLAKE2B hashing
qtegrity	Build qtegrity applet, this adds additional dependencies for OpenSSL

tatt

templates	Install template scripts to be used with tatt

app-shells

autojump

ipython	Add support for dev-python/ipython

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'

bash-completion

eselect	Support blacklisting of completions via 'eselect bash-completion'. This enables custom Gentoo patching of upstream completion loader.

dash

vanilla	Support echo -n, and enable echo -e all the time (unsupported)

mksh

lksh	variant that uses POSIX-compliant arithmetics with the host “long” data type and is automatically in POSIX mode when called as /bin/sh

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.

shish

diet	Use dev-libs/dietlibc

app-text

asciidoc

highlight	Enable source code highlighting

atril

caja	Enable property page extension in mate-base/caja
dvi	Enable build-in DVI viewer
epub	Enable build-in DVI viewer using net-libs/webkit-gtk
t1lib	Enable the Type-1 fonts for the build-in DVI viewer (media-libs/t1lib)
xps	Enable XPS viewer using app-text/libgxps

blogc

git	Build blogc-git-receiver tool
httpd	Build blogc-runserver tool
make	Build blogc-make tool

cb2bib

webengine	Use dev-qt/qtwebengine instead of dev-qt/qtwebkit

coolreader

wxwidgets	Use x11-libs/wxGTK instead of Qt5

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)

dbacl

interactive	Enable the interactive mailinspect ability

dblatex

inkscape	Use inkscape to convert SVG. Disable to use gnome-base/librsvg instead.

dictd

judy	Build Judy-based (dev-libs/judy) plugin implementing fast "exact" and especially "lev" strategies
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)

docbook-xsl-ns-stylesheets

ruby	Install the Ruby-based dbtoepub script; requires an interpreter compatible with app-eselect/eselect-ruby.

docbook-xsl-stylesheets

ruby	Install the Ruby-based dbtoepub script; requires an interpreter compatible with app-eselect/eselect-ruby.

ebook-tools

lit2epub	Install lit2epub script

editorconfig-core-c

cli	Install command line interface.

enchant

aspell	Adds support for app-text/aspell spell checker
hunspell	Adds support for app-text/hunspell spell checker

evince

dvi	Enable the built-in DVI viewer
nautilus	Enable property page extension in gnome-base/nautilus
postscript	Enable support for PostScript and Adobe Illustrator documents with app-text/libspectre
spell	Enable inline spell check for annotations via app-text/gspell
t1lib	Enable the Type-1 fonts for the built-in DVI viewer (media-libs/t1lib)
xps	Enable XPS viewer using app-text/libgxps

getxbook

ocr	Use app-text/tesseract for optical character recognition

ghostscript-gpl

unicode	Add support for unicode passwords via net-dns/libidn

groonga

abort	Enable query abortion
benchmark	Build benchmark programs
dynamic-malloc-change	Allow dynamic memory allocation change for testing
exact-alloc-count	Atomic counting for memory alloc count
fmalloc	Make memory allocation failed in specified condition for debug
futex	Use futex
libevent	Enable dev-libs/libevent used for suggestion
mecab	Use app-text/mecab for morphological analysis
msgpack	Enable dev-libs/msgpack used for suggestion
nfkc	Use nfkc based utf8 normalization
sphinx	Enable document generation by app-misc/sphinx
uyield	Build for detecting race conditions
zeromq	Enable net-libs/zeromq used for suggestion

hyperestraier

mecab	Enable app-text/mecab support for Estraier

kbibtex

webengine	Use dev-qt/qtwebengine for HTML previews
zotero	Enable support for synchronisation with zotero.org web service

lcdf-typetools

kpathsea	Enable integration with kpathsea search library (TeX related)

libebook

tools	Build file conversion tools

libmwaw

tools	Build file conversion tools

libqxp

tools	Build file conversion tools

libstaroffice

tools	Build conversion tools
zlib	Enable support for compressed data

libwpd

tools	Build file conversion tools

libwps

tools	Build file conversion tools

mathtex

png	Generate png images by default instead of gif

msort

heap	Use heap instead of alloca()
icu	Use dev-libs/icu instead of dev-libs/libutf8proc.
libuninum	Use dev-libs/libuninum for conversion.

pandoc

embed-data-files	Embed data files in binary for relocatable executable.
http-conduit	Enable downloading of resources over https.
https	Enable support for downloading of resources over https.
make-pandoc-man-pages	Build program to regenerate pandoc man pages from README.
network-uri	Get Network.URI from the network-uri package.
trypandoc	Build trypandoc cgi executable.
weigh-pandoc	Build weigh-pandoc to measure memory usage.

pastebinit

crypt	Install pbputs for gpg-encrypted pastes

pdfgrep

unac	Removing accents and ligatures before search

pelican

markdown	Markdown support

podofo

boost	Add support for boost
tools	Build and install commandline tools.

poppler

nss	Enable signatures handling with dev-libs/nss
utils	Install command-line PDF converters and various utilities.

qpdf

perl	Install fix-qdf tool (for reverting PDF edits) written in perl

qpdfview

fitz	Use experimental fitz rendering, provided by app-text/mupdf, instead of poppler
synctex	Add support for searching TeX sources

robodoc

examples	Installs usage examples in /usr/share for Perl

sdcv

darkterm	Improve readability of color output on terminals with dark background.

sgmltools-lite

jadetex	Add support for app-text/jadetex (for processing tex files produced by the TeX backend of Jade)

sigil

plugins	Installed needed Python packages for using Sigil plugins
system-mathjax	Use the system-wide dev-libs/mathjax instead of bundled

stardict

advertisement	Enable stardict advertisements plugin
cal	Enable calendar support using cal program
dictdotcn	Enable dict.cn network plugin (for Chinese language)
espeak	Enable text to speech synthesizer plugin using app-accessibility/espeak engine
flite	Enable text to speech synthesizer plugin using app-accessibility/flite engine
fortune	Enable plugin to read fortune messages using games-misc/fortune-mod. You may consider installing games-misc/fortune-mod-all to get all fortune messages.
gucharmap	Enable plugin for unicode symbols description using gnome-extra/gucharmap
htmlparse	Enable plugin to parse dictionaries with html content
info	Enable plugin to read info pages
man	Enable plugin to read manual pages
powerwordparse	Enable plugin to parse powerword dictionaries
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 dictionary management tools and converters from various dictionary formats
updateinfo	Enable plugin to check for stardict updates
wikiparse	Enable plugin to parse dictionaries in wikimedia format
wordnet	Enable wordnet plugin to find similar English words using lexical database
xdxfparse	Enable plugin to parse dictionaries in xdxf (XML Dictionary eXchange Format)
youdaodict	Enable youdao.com network plugin (for Chinese language)

sword

clucene	Use dev-cpp/clucene for lucene search support

tessdata_best

osd	Enable support orientation and script detection.

tessdata_fast

osd	Enable support orientation and script detection.

tessdata_legacy

math	Enable support for recognition of equations.
osd	Enable support orientation and script detection.

tesseract

math	Enable support for recognition of equations.
opencl	Enable opencl support for speedup using GPU computation.
osd	Enable support orientation and script detection.
scrollview	Install viewer to debug recognition (ScrollView).
training	Install training applications to add support for new languages.

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
epspdf	Add support for app-text/epspdf, a tool for converting [e]ps 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)
luatex	Add extra support for luatex
metapost	Add support for metapost: A tool for creating graphics in scalable PostScript
music	Add support for music typesetting (dev-texlive/texlive-music)
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-mathscience)
tex4ht	Add support for dev-tex/tex4ht (for converting (La)TeX to (X)HTML, XML and OO.org)
texi2html	Add support for app-text/texi2html which converts texi files to HTML
xetex	Add support for XeTeX macros (dev-texlive/texlive-xetex)
xindy	Add support for app-text/xindy, a flexible indexing system

texlive-core

luajittex	Add support for LuaJitTeX: LuaTeX based on LuaJIT which is usually faster.
xetex	Add support for XeTeX: a TeX system with Unicode and modern font technologies.

wdiff

experimental	Build experimental utilities (mdiff, unify, wdiff2)

webgen

builder	Enable programmatic HTML/XML generation
highlight	Enable syntax highlighting for certain plugins
markdown	Markdown support

writerperfect

abiword	Add support for abiword format using app-text/libabw
ebook	Add support for various ebook formats using app-text/libebook
epub	Add support for conversion to ePub format using app-text/libepubgen
freehand	Add support for freehand format using media-libs/libfreehand
gsf	Add support for structured files using gnome-extra/libgsf
keynote	Add support for keynote format using app-text/libetonyek
mspub	Add support to mspub format using app-text/libmspub
mwaw	Add support to mwaw formats using app-text/libmwaw
pagemaker	Add support to pagemaker formats using media-libs/libpagemaker
qxp	Add support for QuarkXpress documents using app-text/libqxp
visio	Add support for visio format using media-libs/libvisio
wpd	Add support for wpd format using app-text/libwpd
wpg	Add support for wpg format using app-text/libwpg
wps	Add support for wps format using app-text/libwps
zmf	Add support for Zoner Callisto/Draw documents format using media-libs/libzmf

wv

tools	Install optional utilities considered deprecated in favor of using AbiWord.

xmlto

text	Support conversion from XML to plain text

xpdf

cmyk	Include support for CMYK rasterization
i18n	Enable support non-UTF8 national charsets
icons	Generate desktop PNG icons using media-gfx/inkscape
libpaper	Use app-text/libpaper to get paper preferences
metric	Use A4 instead of US Letter paper size by default for PostScript output. This option has effect only if libpaper USE flag is disabled
opi	Include support for OPI (Open Prepress Interface) comments
textselect	Allow text selection
utils	Install command-line PDF converters and various utilities

zathura

synctex	Use libsynctex to get latex codeline from pdf

zathura-meta

cb	Install plug-in for ComicBook support

app-vim

gentoo-syntax

ignore-glep31	Remove GLEP 31 (UTF-8 file encodings) settings

app-xemacs

xemacs-packages-all

mule	Add multi-language support to XEmacs

dev-ada

gnat_util

shared	Build gnat_util shared library
static-pic	Build gnat_util static library with pic code

gnatcoll-bindings

shared	Build shared library
static-pic	Build shared library

gnatcoll-core

shared	Build shared library
static-pic	Build static library with pic code

gnatcoll-db

db2ada	Build gnatcoll_db2ada
gnatinspect	Build gnatinspect
shared	Build shared library
sql	Build sql library
static-pic	Build shared library
xref	Build xref library

gtkada

shared	Build gtkada as shared library

libadalang

shared	Build shared library

libgpr

shared	Build shared library
static-pic	Build static library with pic code

xmlada

shared	Build shared library
static-pic	Build static library with pic code

dev-cpp

eigen

c++11	Build using the C++11 standard
cuda	Build with cuda support

glog

gflags	Use dev-cpp/gflags for flag parsing
unwind	Use sys-libs/libunwind for stack unwinding instead of glibc/gcc (may be more reliable on x86_64)

libcmis

man	Build and install man pages
tools	Build client tool for testing and viewing features

libjson-rpc-cpp

http-client	Build support for HTTP client using net-misc/curl
http-server	Build support for HTTP server using net-libs/libmicrohttpd
redis-client	Build support for Redis client using dev-libs/hiredis
redis-server	Build support for Redis server using dev-libs/hiredis
stubgen	Build header stub code generator (needed for development and when pregenerated headers are not bundled)

sourcetrail

examples	Install example projects.

dev-db

aerospike-server-community

tools	Install extra tools

clickhouse

client	Build CLI client.
kafka	Enables support for kafka consumer.
mongodb	Enabled support for MongoDB-based dictionaries
server	Build server.
tools	Build various tools, like benchmark, copier, etc.
zookeeper	Enable support for clustering (based on Zookeeper).

etcd

server	Installs etcd daemon

firebird

server	Install the server components of Firebird, not just the client
xinetd	Install ClassicServer

mariadb

backup	Build mariadb-backup which supports SST and hot backup of InnoDB, Aria and MyISAM including compression and encryption
client-libs	Build the client libraries from the server package instead of the C Connector packages
extraengine	Add support for alternative storage engines (Archive, CSV, Blackhole, Federated(X), Partition)
galera	Enables galera replication
innodb-lz4	Enables lz4 compression methods for InnoDB/XtraDB
innodb-lzo	Enables lzo compression methods for InnoDB/XtraDB
innodb-snappy	Enables snappy compression methods for InnoDB/XtraDB using app-arch/snappy
jdbc	Enable the CONNECT engine to access foreign databases via JDBC
latin1	Use LATIN1 encoding instead of UTF8
libressl	Enable SSL connections and crypto functions using dev-libs/libressl
mroonga	Add support for the Mroonga engine for interfacing with the Groonga text search
numa	Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
oqgraph	Add support for the Open Query GRAPH engine
pam	Enable the optional PAM authentication plugin for the server
profiling	Add support for statement profiling (requires USE=community).
rocksdb	Add support for RocksDB; a key/value, LSM database optimized for flash storage
server	Build the server program
sphinx	Add suport for the sphinx full-text search engine
sst-mariabackup	Add tools needed to support the mariabackup SST method
sst-rsync	Add tools needed to support the rsync SST method
sst-xtrabackup	Add tools needed to support the xtrabackup and xtrabackup-v2 SST methods
systemtap	Build support for profiling and tracing using dev-util/systemtap
test	Install upstream testsuites for end use.
tokudb	Add support for TokuDB storage engine
yassl	Enable SSL connections and crypto functions using the bundled yaSSL

mongodb

lto	Adds support for link time optimization
mms-agent	Install the MongoDB Monitoring Service agent
tools	Install the MongoDB tools (mongoimport, mongodump...) from app-admin/mongo-tools

mycli

ssh	Add support for connection over SSH tunnel

mysql

cjk	Add CJK support for InnoDB fulltext search using app-text/mecab
client-libs	Build the client libraries from the server package instead of the C Connector packages (not recommended)
experimental	Build experimental features aka "rapid" plugins
latin1	Use LATIN1 encoding instead of UTF8
libressl	Enable SSL connections and crypto functions using dev-libs/libressl
numa	Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
profiling	Add support for statement profiling (requires USE=community).
router	Build the MySQL router program
server	Build the server program
systemtap	Build support for profiling and tracing using dev-util/systemtap
test	Install upstream testsuites for end use.
yassl	Enable SSL connections and crypto functions using the bundled yaSSL

mysql-cluster

client-libs	Build the client libraries from the server package instead of the C Connector packages (not recommended)
extraengine	Add support for alternative storage engines (Archive, CSV, Blackhole, Federated(X), Partition)
latin1	Use LATIN1 encoding instead of UTF8
libressl	Enable SSL connections and crypto functions using dev-libs/libressl
numa	Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
profiling	Add support for statement profiling (requires USE=community).
server	Build the server program
systemtap	Build support for profiling and tracing using dev-util/systemtap
test	Install upstream testsuites for end use.
yassl	Enable SSL connections and crypto functions using the bundled yaSSL

mysql-connector-c++

gcov	Build coverage support
legacy	Build the legacy 1.x API as well as the DevX API

opendbx

man	Build and install man pages

oracle-instantclient

jdbc	Support for XA, Internationalization, and RowSet operations under JDBC
odbc	Libraries for enabling ODBC applications
precomp	"proc" binary and related files to precompile a Pro*C application
sdk	Header files and an example makefile for developing Oracle applications
sqlplus	The SQL*Plus command line tool for SQL and PL/SQL queries
tools	Data Pump, SQL*Loader and Workload Replay Client

percona-server

cjk	Add CJK support for InnoDB fulltext search using app-text/mecab
client-libs	Build the libmysqlclient libraries
experimental	Build experimental features aka "rapid" plugins
latin1	Use LATIN1 encoding instead of UTF8
libressl	Enable SSL connections and crypto functions using dev-libs/libressl
numa	Enable NUMA support using sys-process/numactl (NUMA kernel support is also required)
profiling	Add support for statement profiling (requires USE=community).
rocksdb	Add support for RocksDB; a key/value, LSM database optimized for flash storage
router	Build the MySQL router program
server	Build the server program
systemtap	Build support for profiling and tracing using dev-util/systemtap
tokudb	Add support for TokuDB storage engine
tokudb-backup-plugin	Builds the TokuDB backup plugin
yassl	Enable SSL connections and crypto functions using the bundled yaSSL

pgbouncer

c-ares	Use c-ares as the DNS backend instead of evdns (libevent).
udns	Use udns as the DNS backend instead of evdns (libevent). Supports IPv4 only.

pgpool2

memcached	Use memcached for query caching.

pgrouting

html	Install HTML formatted documentation

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

address-standardizer	Normalize US and CA postal addresses
gtk	Build graphical interface for shp2pgsql (shp2pgsql-gui)
mapbox	Add capability to transform geometry into Mapbox Vector Tile
topology	Build topology spatial types and functions

postgresql

llvm	Add support for llvm JIT engine
pg-legacytimestamp	Use double precision floating-point numbers instead of 64-bit integers for timestamp storage.
server	Disable to build and install the clients and libraries only.
uuid	Enable server side UUID generation (via dev-libs/ossp-uuid).

psqlodbc

iodbc	Use dev-db/libiodbc. Disable to use dev-db/unixODBC.

redis

tcmalloc	Use tcmalloc from dev-util/google-perftools for allocations.

spatialite

geos	Add the sci-libs/geos library for exact topological tests
proj	Add the sci-libs/proj library for reprojection features
xls	Add the dev-libs/freexl library for xls import support

sqldeveloper

sybase	Add support for the Sybase SQL Database Server

sqlite

secure-delete	Enable overwriting of deleted content with zeros by default (http://sqlite.org/pragma.html#pragma_secure_delete), causing some performance penalty
tools	Install additional tools

sqlitestudio

cli	Build CLI interface

tokumx

pax_kernel	Apply patch needed for hardened kernels

unixODBC

minimal	Disable bundled drivers and extra libraries (most users don't need these)
odbcmanual	Administrator, Internal Structure, Programmer and User documentation

dev-embedded

avrdude

ftdi	Enable support for USB FTDI chips via dev-embedded/libftdi

libftdi

tools	build ftdi_eeprom helper tool

openocd

cmsis-dap	Support for CMSIS-DAP compliant adapters
dummy	Build the dummy port driver
ftdi	Enable support for USB FTDI chips via dev-embedded/libftdi
jlink	Build the SEGGER J-Link driver
parport	Enable support for parport JTAG devices
verbose-io	Verbose IO and comm JTAG and USB messages

sdcc

avr	Add support for AVR -- not supported upstream
boehm-gc	Enable Hans Boehm's garbage collector dev-libs/boehm-gc
device-lib	Enable built of devices libraries
ds390	Add support for Dallas DS390
ds400	Add support for Dallas DS400
ez80-z80	Add support for EZ80-Z80
gbz80	Add support for Gameboy gbz80
hc08	Add support for Freescale/Motorola HC08 based
mcs51	Add support for Intel mcs51
non-free	Enable non-free runtime library parts
packihx	Enable Intel HEX files pack utility
pdk13	Add support for PDK13
pdk14	Add support for PDK14
pdk15	Add support for PDK15
pdk16	Add support for PDK16
pic14	Add support for Microchip 14 bits PICs
pic16	Add support for Microchip 16 bits PICs
r2k	Add support for Rabbit 2000
r3ka	Add support for Rabbit 3000A
s08	Add support for Freescale/Motorola S08
sdbinutils	Enable SDCC library archive utilities sdar, sdranlib, sdnm
sdcdb	Enable SDCC source level debugger
sdcpp	Enable SDCC preprocessor based on GCC cpp
stm8	Add support for STMicroelectronics STM8
tlcs90	Add support for TLCS-90
ucsim	Enable software simulator for microcontrollers
z180	Add support for Zilog Z180
z80	Add support for Zilog Z80

urjtag

ftd2xx	Enable support for USB FTDI chips via dev-embedded/libftd2xx
ftdi	Enable support for USB FTDI chips via dev-embedded/libftdi

dev-games

aseprite

bundled-libs	Use the upstream provided bundled version of allegro 4.4.2
gtk3	Enable support for the experimental native GTK File Dialog

cegui

devil	Build the DevIL based ImageCodec module
freeimage	Build the FreeImage based ImageCodec module
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

guichan

allegro	Build the Allegro frontend

mygui

l10n_ru	Install some additional russian docs if 'doc' useflag enabled
ogre	Use the ogre render subsystem. (cannot combine with opengl)
opengl	Use the opengl render subsystem. (cannot combine with ogre)
plugins	Build MyGUI plugins
samples	Install MyGUI demos (needs ogre USE flag)
tools	Build the tools for development

ode

double-precision	more precise calculations at the expense of speed
gyroscopic	enable gyroscopic term (may cause instability)

ogre

boost	Enable boost support
cache	Enable GL state cache support
cg	NVIDIA toolkit plugin
double-precision	More precise calculations at the expense of speed
egl	Use egl instead of glx
experimental	Build experimental BETA component 'HLMS'
freeimage	Support images via media-libs/freeimage
gl3plus	Build OpenGL 3+ RenderSystem (EXPERIMENTAL)
gles2	Build OpenGL ES 2.x RenderSystem
gles3	Enable OpenGL ES 3.x Features
json	Use dev-libs/rapidjson (needed by Hlms JSON materials)
legacy-animations	Use the skeletal animation from 1.x. It's much slower, but the new system is still experimental.
mobile	Build for OpenGL ES 2.0 only and use the mobile variants of the PBS and unlit material systems.
ois	Pull in Object-oriented Input System library dev-games/ois for samples
poco	When USE=threads, use poco for threading
resman-pedantic	Resource Manager PEDANTIC : require an explicit resource group. Case sensitive lookup. Some demos might not work with this setting. (default: case-insensitive + sensitive lookup in all groups)
tbb	When USE=threads, use tbb for threading
tools	Build and install helper tools

openscenegraph

asio	Enable support for dev-cpp/asio library
dicom	Enable DICOM medical image file support via sci-libs/dcmtk
egl	Enable EGL support
fox	Build examples using x11-libs/fox library
gdal	Enable support for sci-libs/gdal library
las	Enable support for geospatial data LAS LiDAR format using sci-geosciences/liblas
openinventor	Build OpenInventor plugin
osgapps	Build osg applications
sdl2	Use media-libs/libsdl2 additionally to media-libs/libsdl
xrandr	Enable support for the X xrandr extension

physfs

7zip	Enable 7zip/lzma archive support
grp	Enable Build Engine GRP archive support
hog	Enable Descent I/II HOG archive support
iso	Enable ISO9660 file support
mvl	Enable Descent I/II MVL archive support
qpak	Enable Quake I/II QPAK archive support
slb	Enable Independence War SLB archive support
vdf	Enable Gothic/Gothic II VDF archive support
wad	Enable Doom WAD archive support

simgear

dns	Enable DNS resolver via net-libs/udns
gdal	Enable alternative terrain engine based on pagedLOD via sci-libs/gdal
subversion	Enable terrasync scenery downloader

dev-haskell

abstract-deque

usecas	Enable the reference implementation to use hardware compare-and-swap.

aeson-pretty

lib-only	don't build 'aeson-pretty' executable.

ansi-terminal

example	Build the example application.

ansi-wl-pprint

example	Build the example application.

authenticate

network-uri	Get Network.URI from the network-uri package

bifunctors

semigroups	You can disable the use of the `semigroups` package using `-f-semigroups`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
tagged	You can disable the use of the `tagged` package using `-f-tagged`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

biosff

fclip	Build the fclip executable.
flower	Build the flower executable.
frecover	Build the frecover executable.

blaze-builder-enumerator

newbuilder	use bytestring-builder instead of blaze-builder-0.3

bytedump

executable	build executable file

bytes

test-doctests	Enable the doctest suite when using the enable-tests option for cabal.

c2hs

regression	run regression tests

cabal-install

network-uri	Get Network.URI from the network-uri package.
noprefs	Ignore 'preferred-versions' file from hackage's tarball.

certificate

executable	Build the executable

cgi

extensible-exceptions-in-base	Required to be enabled for >=dev-lang/ghc-7.
network-uri	Get Network.URI from the network-uri package.

chell

color-output	use colors in program output

citeproc-hs

bibutils	use Chris Putnam's app-text/bibutils
embed-data-files	Embed locale files into the library (needed for windows packaging)
hexpat	use dev-haskell/hexpat instead of dev-haskell/xml for XML parsing
network	use dev-haskell/network and dev-haskell/http to retrieve CSL file from URIs
small-base	Choose the new smaller, split-up base package.
unicode-collation	Use Haskell bindings to the dev-libs/icu

cmark

system-cmark	use app-text/cmark instead of bundled copy

cmdargs

quotation	Build quote module
testprog	Build the test program

comonad

containers	You can disable the use of the `containers` package using `-f-containers`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
contravariant	You can disable the use of the `contravariant` package using `-f-contravariant`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If disabled we will not supply instances of `Contravariant`
distributive	You can disable the use of the `distributive` package using `-f-distributive`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If disabled we will not supply instances of `Distributive`
test-doctests	Run the doctests test suite

conduit

nohandles	experimental code to use raw system calls in place of handles. Not recommended for general use

configfile

buildtests	Build the executable to run unit tests.

contravariant

safe	Get Safe guarantees rather than merely Trustworthy, but with worse constant factors.
semigroups	You can disable the use of the `semigroups` package using `-f-semigroups`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
statevar	You can disable the use of the `StateVar` package using `-f-StateVar`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
tagged	You can disable the use of the `tagged` package on older versons of GHC using `-f-tagged`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

cpu

executable	build 'cpuid' tool

crypto-api

all-cpolys	Build all the CMAC polynomes up to 10000 bits instead of just the usual ones

crypto-conduit

conduit11	Use conduit >= 1.1.

cryptohash

cryptoapi	Defines crypto-api instances

cryptonite

cpu-flags-x86-rdrand	allow compilation with RDRAND on system and architecture that supports it
integer-gmp	Whether or not to use GMP for some functions

dav

network-uri	Get Network.URI from the network-uri package.

distributive

lib-werror	Compile with the ghc -Werror option

encoding

systemencoding	Provide the getSystemEncoding action to query the locale.

entropy

halvm	Build for the HaLVM.

filestore

maxcount	Make use of a recent (>= 2.3.0) Darcs feature which vastly improves the performance of 'latest'. You should disable this flag if you plan to use gitit with an older version of Darcs, or 'latest' will raise an error.

foundation

experimental	enable building experimental features, known as highly unstable or without good support cross-platform

glib

closure-signals	Use the the GClosure-based signals implementation.

gtk

deprecated	Include definitions in this library that are considered obsolete.
fmode-binary	Set the default file translation mode for file I/O operations to _O_BINARY.
gio	Depend on GIO package, thereby enabling certain features.

gtk2hs-buildtools

closuresignals	Use the the GClosure-based signals implementation.

gtk3

fmode-binary	Set the default file translation mode for file I/O operations to _O_BINARY.
gio	Depend on GIO package, thereby enabling certain features.

hackage-security

use-network-uri	Get Network.URI from the network-uri package.

happstack-server

network-uri	Get Network.URI from the network-uri package
template-haskell	Description: Template Haskell is available on this system

hashed-storage

diff	Provide the Storage.Hashed.Diff module.
hpc	Compile with the profiling ghc flag -fhpc.

hashtables

bounds-checking	if on, use bounds-checking array accesses
portable	if on, use only pure Haskell code and no GHC extensions.
unsafe-tricks	turn on unsafe GHC tricks

haskeline

legacy-encoding	Use legacy iconv encoding for POSIX. This is only intended for testing.
libiconv	Explicitly link against the libiconv library.
terminfo	Use the terminfo package for POSIX consoles.

hdbc-odbc

buildstresstest	Build stress test

hdbc-sqlite3

buildtests	Build the executable to run unit tests
splitbase	Choose the new smaller, split-up package.

hexpat

bundled-expat	Use bundled expat instead of dev-libs/expat

highlighting-kate

executable	Build the Highlight executable.
pcre-light	Use the pcre-light library instead of regex-pcre-builtin.

hit

executable	Build the executable

hlint

gpl	Use GPL libraries, specifically hscolour.

hps

build-exec	Build the `hps-fractals' executable

hs3

network-uri	Get Network.URI from the network-uri package.

hslogger

buildtests	Build the executable to run unit tests.

hslua

apicheck	Compile Lua with -DLUA_USE_APICHECK..
system-lua	Use the system-wide lua instead of the bundled copy.

hsopenssl

fast-bignum	Enable fast moving of bignums between OpenSSL and GMP (GHC Only)

http

conduit10	Use version 1.0.x or below of the conduit package (for the test suite).
network-uri	Get Network.URI from the network-uri package.

http-api-data

use-text-show	Use text-show library for efficient ToHttpApiData implementations

http-client

network-uri	Get Network.URI from the network-uri package.

http-streams

network-uri	Get Network.URI from the network-uri package.

httpd-shed

buildexamples	Build example executables.
network-uri	Get Network.URI from the network-uri package.

hxt

network-uri	Get Network.URI from the network-uri package.

icalendar

network-uri	use network-uri package

json

generic	Add support for generic encoder (dev-haskell/syb)
mapdict	Encode Haskell maps as JSON dicts
parsec	Add support for parsing with Parsec
pretty	Add support for using pretty printing combinators

language-dot

executable	Build the `ppdot' executable

lens

benchmark-uniplate	Enable benchmarking against Neil Mitchell's uniplate library for comparative performance analysis. Defaults to being turned off to avoid the extra dependency.
dump-splices	Build and run the doctests test-suite.
inlining	Generate inline pragmas when using template-haskell. This defaults to enabled, but you can to shut it off to benchmark the relative performance impact, or as last ditch effort to address compile errors resulting from the myriad versions of template-haskell that all purport to be 2.8.
j	Attempt a parallel build with GHC 7.8.
lib-werror	Turn on ghc-options: -Werror
old-inline-pragmas	Some 7.6.1-rc1 users report their TH still uses old style inline pragmas. This lets them turn on inlining.
safe	Disallow unsafeCoerce
test-doctests	Build and run the doctests test-suite.
test-hlint	You can disable the hlint test suite with -f-test-hlint
test-hunit	You can disable the hunit test suite with -f-test-hunit
test-properties	Build the properties test if we're building tests
test-templates	Build the test templates if we're building tests
trustworthy	Assert that we are trustworthy when we can

lifted-async

monad-control-1	Use moand-control == 1.*

linear

template-haskell	You can disable the use of the `template-haskell` package using `-f-template-haskell`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

monad-control

instancest	If enabled this package will export MonadBaseControl instances for the lazy and strict ST monad. If disabled these instances are only exported when base >= 4.4. If enabled it is required that the transformer-base package exports MonadBase instances for ST. It will do this by default.

monad-logger

template-haskell	Enable Template Haskell support.

monad-par

chaselev	Use Chase-Lev Deques for higher-perf work-stealing.

nats

hashable	You can disable the use of the `hashable` package using USE=-hashable. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If set we will not supply an instance of `Hashable`.

network-data

small-base	Build the split-up base package.

pandoc-citeproc

bibutils	use Chris Putnam's app-text/bibutils
embed-data-files	Embed locale files into the library (needed for windows packaging)
hexpat	use dev-haskell/hexpat instead of dev-haskell/xml for XML parsing
network	use dev-haskell/network and dev-haskell/http to retrieve CSL file from URIs
small-base	Choose the new smaller, split-up base package.
test-citeproc	Build the test-citeproc program
unicode_collation	Use Haskell bindings to the dev-libs/icu

parsec-numbers

parsec1	use dev-haskell/parsec1 instead of dev-haskell/parsec

persistent

nooverlap	Use OverlappingInstances only for String. Only developers should use this.

persistent-sqlite

build-sanity-exe	Build a sanity check test executable.

pointed

comonad	optional instances
containers	optional instances
kan-extensions	optional instances
semigroupoids	optional instances
semigroups	optional instances
stm	optional instances
tagged	optional instances
transformers	optional instances
unordered-containers	optional instances

publicsuffixlist

create	export Network.PublicSuffixList.Create module
runtimelist	read suffix list from dist at startup instead of embedding list into library

quickcheck

template-haskell	Enable additional test modules requiring Template Haskell support.

recaptcha

network-uri	Get Network.URI from the network-uri package.

reflection

template-haskell	Enable template haskell.

rfc5051

mkunicodedata	build codes generator itself

sandi

with-conduit	Build with conduit

scientific

bytestring-builder	Provide the Data.ByteString.Builder.Scientific module (requires bytestring >= 0.10).

semigroupoid-extras

profunctors	You can disable the use of the `profunctors` package using `-f-profunctors`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

semigroupoids

comonad	You can disable the use of the `comonad` package using `-f-comonad`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If disabled we will not supply instances of `Comonad`
containers	You can disable the use of the `containers` package using `-f-containers`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
contravariant	You can disable the use of the `contravariant` package using `-f-contravariant`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If disabled we will not supply instances of `Contravariant`
distributive	You can disable the use of the `distributive` package using `-f-distributive`. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If disabled we will not supply instances of `Distributive`
tagged	You can disable the use of the `tagged` package using `-f-tagged`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

semigroups

binary	provide instances for binary package
bytestring	You can disable the use of the `bytestring` package using USE=-bytestring. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
containers	You can disable the use of the `containers` package using USE=-containers. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
deepseq	You can disable the use of the `deepseq` package using `-f-deepseq`. Disabing this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
hashable	You can disable the use of the `hashable` package using USE=-hashable. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users. If set we will not supply an instance of `Hashable`.
text	You can disable the use of the `text` package using USE=-text. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.
transformers	provide instances for transformers package.
unordered-containers	You can disable the use of the `unordered-containers` package using USE=-unordered-containers. Disabling this is an unsupported configuration, but it may be useful for accelerating builds in sandboxes for expert users.

sendfile

portable	Explicitly enable portable sendfile support (implemented in Haskell)

sha

exe	Build a sha1 and a sha384 executable similar to 'md5sum'.

shakespeare

test-coffee	Render tests through coffeescript render function.
test-export	Test export.
test-roy	Render tests through roy render function.

shakespeare-js

test-coffee	Test coffee.
test-export	Test export.
test-roy	Test roy.

shelly

lifted	run the tests against Shelly.Lifted

shuffle

network-uri	Get Network.URI from the network-uri package.

simple-sendfile

allow-bsd	Allow use of BSD sendfile (disable on GNU/kFreeBSD)

skein

big-endian	When manually selecting the endianness, use big-endian (default is little-endian)
force-endianness	Use a manually selected endian when compiling (see flag 'big-endian')
reference	Use the reference implementation instead of the optimized one

skylighting

executable	Build the skylighting executable.

snap-core

portable	No non-haskell unportable code.

snap-server

build-pong	Build a server that just returns "PONG"
openssl	enable https support using dev-haskell/hsopenssl
portable	no non-haskell unportable code.

tagsoup

download	Build with Download module.
testprog	Build the test program.

tasty

colors	Enable colorful output

tasty-quickcheck

old-quickcheck	Use Quick-Check < 2.7.

texmath

executable	Compile test executable.
network-uri	Get Network.URI from the network-uri package.

text

developer	operate in developer mode

thyme

bug-for-bug	bug-for-bug compatibility with time
lens	use the full lens package
show-internal	instance Show of internal representation

tls

compat	Accept SSLv2 compatible handshake.
network	Use the base network library.

transformers-base

orphaninstances	Build instances for orphan datatypes.

transformers-compat

three	Use transformers-0.3

unix-compat

old-time	build against old-time package

uuagc

with-loag	Use dev-haskell/minisat external SAT-solver to schedule all Linear Ordered AGs.

vector

boundschecks	Enable bounds checking
internalchecks	Enable internal consistency checks at the cost of a significant performance penalty
unsafechecks	Enable bounds checking in unsafe operations at the cost of a significant performance penalty

vector-algorithms

bench	Build a benchmarking program.
boundschecks	Enable bounds checking.
internalchecks	Enable internal consistency checks at the cost of a significant performance penalty.
properties	Enable quickcheck tests.
unsafechecks	Enable bounds checking in unsafe operations at the cost of a significant performance penalty.

void

safe	dissable effective but unsafe coersions

wai-app-static

print	print debug info.

warp

allow-sendfilefd	Allow use of sendfileFd (not available on GNU/kFreeBSD).
warp-debug	Add additional debuging information

x11

screensaver	whether to build XScreenSaver.

x509-store

executable	Build the executable

xss-sanitize

network-uri	Get Network.URI from the network-uri package.

yaml

no-examples	don't build the examples
no-exe	don't install the yaml2json executable
no-unicode	Don't enable unicode output. Instead, unicode characters will be escaped.
system-libyaml	Use system libyaml instead on generic one

yesod-auth

network-uri	Get Network.URI from the network-uri package

yesod-form

network-uri	Get Network.URI from the network-uri package

zip-archive

executable	Build the Zip executable.

zlib

non-blocking-ffi	Execute FFI calls in the context of haskell thread.

dev-java

ant

antlr	Enable ANTLR Ant tasks
bcel	Enable bcel (bytecode manipulation) Ant tasks
bsf	Enable support for Apache Bean Scripting Framework (dev-java/bsf)
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
junit	Enable JUnit Ant tasks
junit4	Enable JUnit4 Ant tasks
junitlauncher	Enable JUnit5 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
swing	Enable Swing Ant tasks
testutil	Enable optional test util classes
xz	Enable XZ Ant tasks

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

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.

gcj-jdk

awt	Install AWT libraries, needed by some GUIs (not needed to build icedtea)

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
gtk	Build with Gtk+ AWT peers
xml	Build with native XML backend

icedtea

cacao	Use the CACAO virtual machine rather than HotSpot.
cups	Link against the CUPS library at compile time, rather than using it dynamically at runtime.
headless-awt	Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
jamvm	Use the JamVM virtual machine rather than HotSpot.
jbootstrap	If possible, recompile the final IcedTea executables with itself.
kerberos	Link against Kerberos in order to obtain the cache location.
nsplugin	Enable browser plugin (NPPlugin), requires also the webstart flag to be enabled.
pax_kernel	Apply patch needed for pax enabled kernels.
pch	Build using pre-compiled headers.
sctp	Build the SCTP NIO channel implementation against lksctp
shenandoah	Include the Shenandoah ultra-low pause time garbage collector (-XX:+UseShenandoahGC) (arm64 and x86_64 only)
smartcard	Build the PCSC driver against pcsc-lite
system-lcms	Build against the system LCMS installation rather than the in-tree copy.
webstart	Enable Web Start support (via NetX).
zero	Enable Zero assembler port (usually for non-HotSpot architectures)

icedtea-bin

headless-awt	Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
webstart	Provide javaws command through symlink to icedtea-web

icedtea-web

javascript	Enable support for using proxy auto config (PAC) files.
nsplugin	Enable the browser plugin (NPPlugin).
tagsoup	Depend on dev-java/tagsoup which allows parsing malformed .jnlp files

jdbc-mysql

c3p0	Enable c3p0 support
log4j	Enable log4 support

jfreesvg

debug	Enable debugging during compilation.

jna

awt	Enables support for Java AWT
nio-buffers	Enables support for NIO buffers

log4j

javamail	Build the SMTPAppender
jms	Build the JMSAppender

lucene

contrib	Include extra functionality from contrib/

miglayout

swt	Add support for the SWT toolkit.

openjdk

gentoo-vm	Allow this JDK to be recognised by Gentoo (package manager, eselect, java-config, EXPERIMENTAL!)
headless-awt	Don't install the X backend for AWT, needed by some GUIs
javafx	Import OpenJFX modules at build time, via dev-java/openjfx
jbootstrap	Build OpenJDK twice, the second time using the result of the first
source	Install JVM sources
systemtap	Enable SystemTAP/DTrace tracing
webstart	Provide javaws command through symlink to icedtea-web

openjdk-bin

gentoo-vm	Allow this JDK to be recognised by Gentoo (package manager, eselect, java-config, EXPERIMENTAL!)
headless-awt	Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
source	Install JVM sources
webstart	Provide javaws command through symlink to icedtea-web

openjdk-jre-bin

gentoo-vm	Allow this JDK to be recognised by Gentoo (package manager, eselect, java-config, EXPERIMENTAL!)
headless-awt	Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
webstart	Provide javaws command through symlink to icedtea-web

openjfx

media	Compile media module, based on gstreamer-minimal (does not pull gstreamer)
source	Install JavaFX sources

oracle-jdk-bin

commercial	Install features requiring a commercial license for production use
gentoo-vm	Allow this JDK to be recognised by Gentoo (package manager, eselect, java-config, EXPERIMENTAL!)
gtk2	Enable GTK+ 2 support in JavaFX
gtk3	Enable GTK+ 3 support in JavaFX
headless-awt	Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
javafx	Install JavaFX libraries
jce	Install Java Cryptographic Extension Unlimited Strength Jurisdiction Policy Files
source	Install JVM (and optionally JavaFX) sources
visualvm	Install VisualVM debugging tool

oracle-jre-bin

commercial	Install features requiring a commercial license for production use
headless-awt	Don't install the X backend for AWT, needed by some GUIs (used to be X flag)
javafx	Install JavaFX libraries
jce	Install Java Cryptographic Extension Unlimited Strength Jurisdiction Policy Files

rxtx

lfd	Installs and uses LockFileServer daemon (lfd)

sbt

binary	Install from (Gentoo-compiled) binary instead of building from sources. Set this when you run out of memory during build.

dev-lang

bas

lr0	Use the LR0 parser instead of the recursive descending parser

crystal

blocking-stdio-hack	Keep STDIO file descriptors in blocking mode.
debug	Build each module as a separate object file. Speeds build up.
xml	Use the dev-libs/libxml2 library to enable Crystal xml module
yaml	Use the dev-libs/libyaml library to enable Crystal yaml module

erlang

hipe	HIgh Performance Erlang extension
kpoll	Enable kernel polling support
pgo	Build erts with profile-guided optimizations

fpc

ide	Build and install the Free Pascal Compiler IDE

gdl

eigen	Build matrix manipulation with dev-cpp/eigen
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)
udunits	Add support for manipulating units of physical quantities

gforth

check	Enable build-time sanity check.

ghc

binary	Install the binary version directly, rather than using it to build the source version.
elfutils	Enable DWARF-based baclktraces using dev-libs/elfutils.
ghcbootstrap	Internal: Bootstrap GHC from an existing GHC installation.
ghcmakebinary	Internal: Build binary friendly for redistribution.
gmp	use dev-libs/gmp for integer operations (works faster, but an external depend).
numa	Enable NUMA thread balancing policy using sys-process/numactl.

gnat-gpl

ada	Build the ADA language (GNAT) frontend
awt	Useful only when building GCJ, this enables Abstract Window Toolkit (AWT) peer support on top of GTK+
bootstrap	Used to bootstrap gnat-gpl
cilk	Support the Cilk Plus language (C/C++ based languages for parallel programming)
fixed-point	Enable fixed-point arithmetic support for MIPS targets in gcc (Warning: significantly increases compile time!)
gcj	Build the GCJ Java language frontend.
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)
mpx	Enable support for Intel Memory Protection Extensions (MPX)
nopie	Disable PIE support (NOT FOR GENERAL USE)
nossp	Disable SSP support (NOT FOR GENERAL USE)
nptl	Enable support for Native POSIX Threads Library, the new threading module (requires linux-2.6 or better usually)
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
pgo	Build GCC using Profile Guided Optimization (PGO)
sanitize	Build support for various sanitizer functions (ASAN/TSAN/etc...)
ssp	Build packages with stack smashing protector on by default
systemtap	enable systemtap static probe points
vtv	Build support for virtual table verification (a C++ hardening feature)

go

gccgo	Bootstrap using sys-devel/gcc[go]
system-bootstrap	Bootstrap using previously installed dev-lang/go

icon

iplsrc	install the icon programming library source

janet

static-libs	install janet static library archive, you must enable this flag for using `jpm build`

jsonnet

custom-optimization	Build with user-specified compiler optimizations (-Os, -O0, -O1, -O2, -O3) from CFLAGS (unsupported)

lazarus

minimal	Don't build extra packages from the bigide component

logtalk

fop	Support for generating pdf documentation using fop
xslt	Support for generating html documentation using xslt

lua

deprecated	make deprecated data structures/routines available
test-complete	Run the complete (non-portable) testsuite

luajit

lua52compat	Enable some upwards-compatible features from Lua 5.2 that are unlikely to break existing code.

mercury

erlang	Support Mercury Erlang grade
trail	Support Mercury trail grades

mercury-extras

tommath	Enable support for tommath library

mlton

binary	install a binary version
bootstrap-smlnj	Boostrap mlton with dev-lang/smlnj (takes a long time)
pax_kernel	Enable if the user plans to run the package under a pax enabled hardened kernel
stage3	After bootstrap building mlton with dev-lang/smlnj, rebuild mlton with the second stage build of mlton (recommended).

moarvm

asan	Enable clang's Address Sanitizer functionality. Expect longer compile time.
clang	Use clang compiler instead of GCC
jit	Enable Just-In-Time-Compiler. Has no effect except on AMD64 and Darwin.
optimize	Enable optimization via CFLAGS
ubsan	Enable clang's Undefined Behavior Sanitizer functionality. Expect longer compile time.

mono

pax_kernel	Enable if the user plans to run the package under a pax enabled hardened kernel
xen	Make mono generate code that is considerably faster on xen VMs but slightly slower on for normal systems.

nqp

clang	Toggle usage of the clang compiler in conjunction with MoarVM
moar	Build the MoarVM backend (experimental/broken)

ocaml

flambda	Enables the Flambda optimizer: A new intermediate representation (introduced in ocaml 4.03) in the depths of the compiler designed to allow for better inlining.
spacetime	Enables the Spacetime memory profiler. See https://caml.inria.fr/pub/docs/manual-ocaml/spacetime.html for more information.

orc

pax_kernel	Apply patch needed for pax enabled kernels.

perl

ithreads	Enable Perl threads, has some compatibility problems

php

argon2	Enable password hashing algorithm from app-crypt/argon2
bcmath	Add support for libbcmath
cli	Enable CLI SAPI
coverage	Include gcov symbols for test coverage and lcov reports. Only useful for extension developers, and requires GCC.
ctype	Enable ctype functions
embed	Enable embed SAPI
enchant	Add supports Enchant spelling library.
ffi	Add foreign function interface (ffi extension) support
fileinfo	Add fileinfo extension support
filter	Add filter extension support
flatfile	Add dbm support for flat files
fpm	Enable the FastCGI Process Manager SAPI
gd	Adds support for gd (bundled with PHP)
hash	Enable the hash extension
inifile	Add dbm support for .ini files
intl	Enables the intl extension for extended internalization support
json	Enable JSON support
ldap-sasl	Add SASL support for the PHP LDAP extension
lmdb	Enable support for dev-db/lmdb db backend
opcache	Enables built-in opcode cache, replacing pecl-apc et al.
pcntl	Add support for process creation functions
pdo	Enable the bundled PDO extensions
phar	Enables the phar extension to provide phar archive support
phpdbg	Enable the PHP Debug Command Line SAPI (like gdb for php)
session-mm	Include dev-libs/mm support for session storage
sharedmem	Add support for shared memory use
simplexml	Support for SimpleXML
sodium	Enable support for crypto through dev-libs/libsodium
sysvipc	Support for System V-compatible inter-process communication
tokenizer	Add support for the PHP file parser
tokyocabinet	Enable support for dev-db/tokyocabinet db backend
wddx	Add support for Web Distributed Data eXchange
webp	Enable webp support for GD in php-7.x
xmlreader	Enable XMLReader support
xmlwriter	Enable XMLWriter support
xslt	Enable the XSL extension
zip-encryption	Enable ZIP file encryption from dev-libs/libzip

polyml

portable	Build the portable interpreter version of Poly/ML instead of native

python

bluetooth	Build Bluetooth protocol support in socket module
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

rakudo

clang	Use Clang to compile the MoarVM backend
moar	Use the MoarVM as backend

ruby

rdoc	Install dev-ruby/rdoc after installing Ruby.
rubytests	Install ruby tests that can only be run after ruby is installed
systemtap	Enable SystemTAP/DTrace tracing

rust

clippy	Install clippy, Rust code linter
miri	Install miri, an interpreter for Rust's mid-level intermediate representation (requires USE=nightly)
nightly	Enable nightly (UNSTABLE) features
parallel-compiler	Build a multi-threaded rustc
rls	Install rls, Rust Language Server (used with IDEs supporting RLS protocol)
rustfmt	Install rustfmt, Rust code formatter
system-bootstrap	Bootstrap using installed rust compiler
system-llvm	Use the system LLVM install
wasm	Build support for the wasm32-unknown-unknown target

rust-bin

clippy	Install clippy, Rust code linter
rustfmt	Install rustfmt, Rust code formatter

scala

binary	Install from (Gentoo-compiled) binary instead of building from sources. Set this when you run out of memory during build.

smlnj

pax_kernel	Enable if the user plans to run the package under a pax enabled hardened kernel

spidermonkey

custom-optimization	Build with user-specified compiler optimizations (-Os, -O0, -O1, -O2, -O3) from CFLAGS (unsupported)
debug	Enable assertions to allow for easier debugging of programs that link to spidermonkey -- note this will often crash software on regular end-user systems
system-icu	Use the system-wide dev-libs/icu instead of bundled -- note, only takes effect when icu flag is enabled
threadsafe	Build a threadsafe version of spidermonkey

swi-prolog

archive	Use libarchive for extension packs
uuid	Use ossp-uuid for UUID pack
yaml	Use libyaml for YAML pack

swig

ccache	build ccache-swig(a fast compiler cache)

vala

valadoc	Installs valadoc documentation generation tool

yap

R	Enable support for connecting R to Prolog

zig

experimental	Enable builds that do not support all of LLVM's target architectures

dev-libs

antlr-c

debugger	Compiles debug info into the library

appstream

apt	Enables Debians APT support

appstream-glib

fonts	Enable fonts support for appstream-builder.
stemmer	Add word stemming via dev-libs/snowball-stemmer.

apr

older-kernels-compatibility	Enable binary compatibility with older kernels
urandom	Use /dev/urandom instead of /dev/random

apr-util

libressl	Use dev-libs/libressl instead of dev-libs/openssl for 'openssl' USE flag
nss	Install apr_crypto_nss module
openssl	Install apr_crypto_openssl module

atcore

gui	Build test GUI

aws-sdk-cpp

access-management	AWS Access Management, a meta-flag that enables: AWS Certificate Manager (ACM): Provision, manage, and deploy SSL/TLS certificates on AWS managed resources. Identity and Access Management (IAM): A web service for securely controlling access to AWS services. Resource Access Manager (RAM): Customers who operate multiple accounts can create resources centrally and use AWS RAM to share them with all of their accounts to reduce operational overhead. Also enables acm-pca, identity-management and sts (Security Token Service).
apigateway	Create and deploy your own REST and WebSocket APIs at any scale. Also enables apigatewaymanagementapi and apigatewayv2.
backup	AWS Backup is a fully managed backup service
batch	Run batch computing workloads on the AWS Cloud
budgets	Use AWS Budgets to plan service usage, service costs, and instance reservations. Also enables the following related modules: AWS Cost Explorer (CE) : Programmatically query cost and usage data. Cost and Usage Report (CUR): Programmatically create, query, and delete AWS Cost and Usage report definitions.
chime	Amazon Chime, a secure, real-time, unified communications service.
cloud-desktop	AWS end user computing services. AppStream 2.0: Fully managed, secure application streaming service. WorkDocs : Fully managed, secure enterprise storage and sharing service. WorkLink : Fully managed, cloud-based service that enables secure, one-click access to internal websites and web apps from mobile devices. WorkMail : Managed email and calendaring service. WorkSpaces : Cloud-based desktop experience for end users.
cloud-dev	Enables in-cloud developer tools: Cloud9 : Cloud-based integrated development environment IDE to write, run, and debug code. CodeBuild : Managed build service that compiles, runs unit tests and produces artifacts. CodeCommit : Privately store and manage Git repositories in the AWS cloud. CodeDeploy : Automate the deployment and updating of applications. CodePipeline: Continuous delivery service to model, visualize, and automate the steps required to release software. CodeStar : Quickly develop, build, and deploy applications on AWS. Queues : Simple queue class. Allows standard queue operations top, delete, and push. Also has higher level, asynchronous interface with callbacks. X-Ray : Provides request tracing, exception collection, and profiling capabilities.
cloud-media	AWS Media modules for transforming, converting, delivering and streaming media. Elastic Transcoder : Convert media files stored in Amazon S3 into media files in the formats required by consumer playback devices. Elemental Media Connect: Secure and flexible transport service for live video. Elemental Media Convert: Format and compress offline video content for delivery to televisions or connected devices. Elemental Media Live : Video service that allows easy and reliable creation of live outputs for broadcast and streaming delivery. Elemental Media Package: Just-in-time video packaging and origination service. (Includes mediapackage-vod) Elemental Media Store : Video origination and storage service.Manage video assets as objects in containers to build dependable, cloud-based media workflows. (Includes mediastore-data) Elemental Media Tailor : Personalization and monetization service that allows scalable server- side ad insertion.
cloud-mobile	AWS Mobile modules for handling mobile application management and delivery. Amplify : Comprehensive set of SDKs, libraries, tools, and documentation for client app development. AppSync : Enterprise level, fully managed GraphQL service with real-time data synchronization and offline programming features. Device Farm: Test iOS, Android and Fire OS apps on real, physical phones and tablets that are hosted by AWS. PinPoint : Engage customers by sending them email, SMS and voice messages, and push notifications. (Includes pinpoint-email and sms-voice) SNS : Amazon Simple Notification Service, see USE flag sns. Also enables mobile and mobileanalytics.
cloudformation	Create and provision AWS infrastructure deployments predictably and repeatedly. Use a template file to create and delete a collection of resources together as a single unit (a stack).
cloudfront	Delivers static and dynamic web content through a worldwide network of edge locations that provide low latency and high performance.
cloudhsm	Secure cryptographic key storage by providing managed hardware security modules in the AWS Cloud. Also enables cloudhsmv2.
cloudsearch	Fully managed service in the cloud to set up, manage, and scale a search solution for websites. Also enables cloudsearchdomain.
cloudwatch	Amazon CloudWatch monitors Amazon Web Services (AWS) resources and the applications run on AWS in real time. The following modules besides monitoring are also enabled: Application Insights: Monitor .NET and SQL Server applications. App Mesh : Monitor and control microservices running on AWS. CloudTrail : Monitor AWS deployments in the cloud by getting a history of AWS API calls, including API calls made via the AWS Management Console, the AWS SDKs, the command line tools, and higher-level AWS services. GuardDuty : Continuous security monitoring service. Health : Provides personalized information about events that can affect the AWS infrastructure, guides through scheduled changes, and accelerates the troubleshooting of issues that affect AWS resources and accounts. Inspector : A security vulnerability assessment service that helps improve the security and compliance of AWS resources. Logs : Monitor, store, and access log files from Amazon EC2 instances, AWS CloudTrail, or other sources.
cognito	Create unique identities, authenticate these identities with identity providers and save mobile user data in the AWS Cloud. Enables cognito-identity, cognito-idp and cognito-sync
config	Provides a detailed view of the resources associated with your AWS account, including how they are configured, how they are related to one another, and how the configurations and their relationships have changed over time.
dlm	Amazon Data Lifecycle Manager (DLM): Manage the lifecycle of AWS resources. Create lifecycle policies to automate operations on specified resources.
ec2	Amazon Elastic Compute Cloud (EC2) is a web service that provides resizeable computing capacity. This flag also enables the following modules: Auto Scaling : Set up dynamic and predictive scaling for scalable AWS resources. Also enables autoscaling-plans and application-autoscaling. Elastic File System: EFS provides file storage for Amazon EC2 instances.
ecr	Amazon Elastic Container Registry (ECR) is a fully managed Docker container registry.
ecs	Amazon Elastic Container Service (ECS) is a highly scalable, fast, container management service.
eks	Amazon Elastic Kubernetes Service (EKS) is a managed service to run Kubernetes on AWS without own Kubernetes clusters.
elasticache	Set up, manage, and scale distributed in-memory cache environments in the AWS Cloud
elasticbeanstalk	Quickly deploy and manage applications in the AWS Cloud.
elasticloadbalancing	Automatically distribute incoming application traffic across multiple targets, such as EC2 instances. Also enables elasticloadbalancingv2.
elasticmapreduce	Amazon Elastic MapReduce (EMR) processes large amounts of data efficiently using Hadoop processing combined with several AWS products.
email	Amazon Simple Email Service (Amazon SES): An email platform to send and receive email using ones own email addresses and domains. See: https://docs.aws.amazon.com/ses/latest/DeveloperGuide/Welcome.html
es	Amazon Elasticsearch Configuration Service (ES) is an API to create, configure, and manage Elasticsearch domains.
events	Serverless event bus service to connect applications with data from a variety of sources. Also enables eventbridge.
fsx	Amazon FSx is a fully managed service to launch and use shared file storage.
globalaccelerator	AWS Global Accelerator is a network layer service for accelerators to improve availability and performance for internet applications used by a global audience.
http	Enable http support via curl
iot	AWS IoT This is a meta-flag for all Internet of Things modules provided by the SDK: iot : enables secure, bi-directional communication between Internet-connected things (such as sensors, actuators, embedded devices, or smart appliances) and the AWS Cloud over MQTT and HTTP. greengrass : Extends AWS onto physical devices so they can act locally on the data they generate. iot1click : A service for simple devices to trigger AWS Lambda functions that execute a specific action. iotanalytics : Provides advanced data analysis for AWS IoT. iotevents : Monitor equipment or device fleets for failures or changes in operation, and trigger actions when such events occur. iotthingsgraph: Integrated set of tools that enable developers to build IoT applications using devices and services that use different data representation standards and communication protocols. Also enables iot1click-devices, iot1click-projects, iot-data, iotevents-data and iot-jobs-data.
kinesis	Amazon Kinesis Collect, process, and analyze video and data streams in real time. The following modules besides kinesis are enabled: firehose : Load data streams into AWS data stores. kinesisanalytics : Process and analyze streaming data using SQL or Java. (Also enables kinesisanalyticsv2) kinesisvideo : Capture, process, and store video streams for analytics and machine learning. Additionally kinesis-video-archived-media and kinesis-video-media are enabled.
kms	AWS Key Management Service (KMS) An encryption and key management service scaled for the cloud.
lambda	AWS Lambda: Run code without provisioning or managing servers.
lex	Amazon Lex is an AWS service for building conversational interfaces into applications using voice and text. Also enables lex-models.
license-manager	Streamlines the process of bringing software vendor licenses to the cloud.
lightsail	The easiest way to get started with AWS for developers who just need virtual private servers
machinelearning	The algorithms of Amazon Machine Learning create machine learning (ML) models by finding patterns in existing data. The service uses these models to process new data and generate predictions for application.
macie	A security service that uses machine learning to automatically discover, classify, and protect sensitive data in AWS.
managedblockchain	Create and manage scalable blockchain networks using popular open source frameworks. Currently, Managed Blockchain supports the Hyperledger Fabric open source framework.
marketplace	AWS Marketplace is an online store where you can buy or sell software that runs on Amazon Web Services (AWS). Marketplace support consists of the marketplacecommerceanalytics module plus: Marketplace Entitlement Service: A contract verification feature that AWS Marketplace sellers can use to verify the amount of the sellers product (for example, end user licenses or storage, data, or compute capacity) the customer has purchased. Marketplace Metering Service : A pricing and metering feature that AWS Marketplace sellers can use to directly charge for their software along one of four dimensions: users, data, bandwidth, or hosts. Also enables pricing.
opsworks	AWS OpsWorks is a simple and flexible way to create and manage stacks and applications. Also enables opsworkscm.
organizations	Account management service that to consolidate multiple AWS accounts into an organization to be centrally managed.
other	This is a meta-flag for rarely needed modules that in themselves need not much build time. If you would like to have any of the following modules to have their own USE flag, please open a bug report and it will most probably get one. The modules are: AWSMigrationHub, alexaforbusiness, clouddirectory, comprehend, comprehendmedical, connect, datapipeline, datasync, directconnect, discovery, dms, docdb, ds, dynamodb, gamelift, glue, groundstation, importexport, kafka, lakeformation, mq, mturk-requester, neptune, quicksight, redshift, robomaker, sdb, service-quotas, servicecatalog, servicediscovery, signer, sms, snowball, ssm, states, storagegateway, support and swf.
personalize	Real-time personalization and recommendations, based on the same technology used at Amazon.com. Also enables personalize-events and personalize-runtime.
polly	Amazon Polly A Text-to-Speech (TTS) cloud service that converts text into lifelike speech. Also enables text-to-speech.
queues	AWS Queues is a simple queue class. Allows standard queue operations top, delete, and push. Also has higher level, asynchronous interface with callbacks.
rds	Amazon Relational Database Service (RDS) is a web service to set up, operate, and scale a relational database in the cloud. Also enables pi (Performance Insights) and rds-data.
rekognition	Add image and video analysis to applications.
resource-groups	AWS Resource Groups and Tag Editor Organize AWS resources into groups, tag resources using virtually any criteria, and manage, monitor, and automate tasks on grouped resources. Also enables resourcegroupstaggingapi. (Resource Groups Tagging API)
route53	AWS Route 53 is a highly available and scalable Domain Name System (DNS) web service. Also enables route53domains and route53resolver.
rtti	Flag to enable/disable rtti within the library
s3	Amazon Simple Storage Service Storage for the internet. Additionally to the s3 module, the following modules are activated: Athena : Interactive query service to analyze data in Amazon S3 using standard SQL. Glacier : Storage solution for cold data. Transfer for SFTP: Transfer files directly into and out of Amazon S3 using SFTP. Also enables s3-encryption, s3control and transfer.
sagemaker	Amazon SageMaker Fully managed machine learning service. With Amazon SageMaker, data scientists and developers can quickly and easily build and train machine learning models, and then directly deploy them into a production-ready hosted environment. Also enables sagemaker-runtime.
secretsmanager	Encrypt, store, and retrieve credentials for databases and other services.
securityhub	Provides a comprehensive view of the security state of AWS resources.
serverlessrepo	AWS Serverless Application Repository Enables teams, organizations, and individual developers to find, deploy, publish, share, store, and easily assemble serverless architectures.
shield	AWS Shield, protection against DDoS attacks
sns	Amazon Simple Notification Service (SNS) is a web service that enables applications, end-users, and devices to instantly send and receive notifications from the cloud.
sqs	Amazon Simple Queue Service (SQS): Fully managed message queuing service that makes it easy to decouple and scale microservices, distributed systems, and serverless applications.
textract	Amazon Textract to add document text detection and analysis to applications.
transcribe	A transcription services for audio files. It uses advanced machine learning technologies to recognize spoken words and transcribe them into text. Also enables transcribestreaming.
translate	A neural machine translation service for translating text to and from English across a breadth of supported languages.
unity-build	Build using a single unified .cpp file for each service library. Reduces the size of static library binaries
waf	The Web Application Firewall (WAF) can monitor web requests that are forwarded to Amazon CloudFront distributions or an Application Load Balancer. Can also be used to block or allow requests based on conditions such as the IP addresses that requests originate from or values in the requests. Also enables fms and waf-regional.

bitset

tcmalloc	Use tcmalloc from dev-util/google-perftools for allocations

boost

context	Build and install the Boost.Context (and Boost.Fiber) library and all other Boost libraries that depend on it
debug	Build and install only the debug version of the Boost libraries. Only enable this flag if you're developing against boost.
doc	Install the full API documentation documentation. This takes over 200MB of extra disk space.
nls	Build libboost_locale. This library requires compatible C library interfaces, which might not be provided by uClibc or other embedded libraries.
numpy	Optionally build NumPy extensions when Boost.Python is enabled
threads	Build multi-thread-compatible libraries instead of single-threaded only.
tools	Build and install the boost tools (bcp, quickbook, inspect, wave)

botan

boost	use dev-libs/boost

check

subunit	Enable support for the subunit unit test protocol

crypto++

asm	Support assembly hand optimized crypto functions (i.e. faster run time)

cudnn

cuda10-1	On nVidia CUDA 10.1.
cuda10-2	On nVidia CUDA 10.2.

cyberjack

tools	Build and install optional management tools.
usb	Enable support for usb based chipcard reader.

cyrus-sasl

authdaemond	Add Courier-IMAP authdaemond unix socket support (net-mail/courier-imap, mail-mta/courier)
ldapdb	Enable ldapdb plugin
openldap	Add ldap support for saslauthd
sample	Enable sample client and server
srp	Enable SRP authentication
urandom	Use /dev/urandom instead of /dev/random

dbus-c++

ecore	Use Ecore integration
glib	Use glib integration

eekboard

libcanberra	Enable support for media-libs/libcanberra
xtest	Enable support for x11-libs/libXtst

efl

bmp	Enable WBMP image loader
dds	Enable DDS image loader
drm	Enable DRM engine
eet	Enable Eet image loader
fribidi	Enable bidirectional text support
gles2	Enable the OpenGL ES GL implementation
glib	Enable dev-libs/glib support
harfbuzz	Enable complex text shaping and layout support
hyphen	Enable text hyphenation support
ibus	Enable Intelligent Input Bus
ico	Enable Ico image loader
json	Enable lottie animation support
luajit	USE dev-lang/luajit instead of dev-lang/lua
mono	Enable mono bindings
physics	Enable Bullet physics effects and support
pmaps	Enable PMAPS image loader
psd	Enable PSD image loader
scim	Enable Smart Common Input Method
system-lz4	Use system liblz4 instead of bundled one
tga	Enable Tga image loader
tgv	Enable Tgv image loader
tslib	Enable x11-libs/tslib for touchscreen events
unwind	Enable debug support via sys-libs/libunwind
vlc	Enable media-video/vlc support
xcf	Enable XCF image loader
xim	Enable X Input Method
xpresent	Enable x11-libs/libXpresent support

elfutils

lzma	Support automatic decompression of LZMA-compressed files and kernel images
threads	Build the libraries with thread safe support
utils	Install command-line utilities (all the eu-* programs)
valgrind	Add support for memory debugging using dev-util/valgrind

ell

glib	Enable dev-libs/glib support

fcgi

html	Install HTML documentation

folks

telepathy	Load contacts from the Telepathy framework
tracker	Load contacts from app-misc/tracker index
utils	Build the folks-inspect utility

fstrm

utils	Build fstrm utility programs

gf2x

custom-tune	Extra long compile time for tuning hardware specific low-level routines
fft	Build an FFT API for multiplication of 2 polynomials over GF(2)

gjs

sysprof	Enable profiling data capture support using dev-util/sysprof-capture

glib

dbus	Enable dependencies required by glib libraries using dbus service to manage settings saving
mime	Pull in shared MIME database that many glib-based applications require at runtime to detect or open files. Warning: do not disable this flag unless installing on a headless server.
systemtap	Build support for profiling and tracing using dev-util/systemtap
utils	Install gtester-report utility to generate test report files for your software; build gresource utility with ELF support.

gmime

smime	Enable experimental S/MIME support

gmp

asm	Enable use of hand optimized assembly routines (faster execution)
pic	Force static libraries to be built as PIC to avoid TEXTRELs.

gobject-introspection

doctool	Install g-ir-doc-tool for generating documentation from introspected data

hidapi

fox	Build a x11-libs/fox GUI

hsa-ext-rocr

deprecated	Install the deprecated debug/trace/profiling library

input-pad

eekboard	Enable support for dev-libs/eekboard
xtest	Enable support for x11-libs/libXtst

intel-neo

l0	Install the oneAPI Level Zero driver alongside the OpenCL one
vaapi	Support the sharing of surfaces with Video Acceleration API (OpenCL Extension #36)

jemalloc

hugepages	Enable transparent huge page support
lazy-lock	Enable lazy locking (only lock when multi-threaded)
prof	Enable allocation profiling
stats	Enable statistics calculation/reporting
xmalloc	Add support for xmalloc (abort-on-out-of-memory)

kreport

marble	Enable displaying of maps using kde-apps/marble
scripting	Support Qml scripting using dev-qt/qtdeclarative

libbase58

tools	Build command line base58 tool

libbytesize

tools	Build bscalc python CLI tool

libcbor

custom-alloc	Custom, dynamically defined allocator support

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.

libcec

cubox	Enable support for enable support for the TDA995x
exynos	Enable support for Exynos chipsets
raspberry-pi	Enable support for the Raspberry Pi
xrandr	Enable detection of active HDMI using xrandr extensions

libcgroup

daemon	Install the configuration tools and init/config files.
tools	Install the cgroup rules processing daemon and init/config files.

libclsync

extra-debug	Enable extra debugging. This will hurt performance badly. Be ready for tons of output.
extra-hardened	Enable extra security checks. This may hurt performance.

libdbusmenu

gtk	Enable support for GTK+2
gtk3	Enable support for GTK+3

libdynd

cuda	Enable NVIDIA CUDA toolkit support
mkl	Enable a plugin for Intel Math Kernel Library sci-libs/mkl

libevent

debug	Support runtime debug mode and malloc hooks (for programmers)

libffi

pax_kernel	Use PaX emulated trampolines, for we can't use PROT_EXEC
test-bhaible	Run extended regression tests (very slow).

libffi-compat

pax_kernel	Use PaX emulated trampolines, for we can't use PROT_EXEC

libflatarray

cuda	Enables plugins for NVIDIA GPUs (e.g. CUDAAllocator)

libgcrypt

o-flag-munging	Enable O-flag mangling during build

libgdata

crypt	Use app-crypt/gcr for keeping tokens and passwords in non-pageable memory for improved security
gnome-online-accounts	Enable net-libs/gnome-online-accounts support

libgit2

gssapi	Enable GSSAPI support for SPNEGO auth
ssh	Enable SSH transport support
trace	Enable tracing support

libgit2-glib

ssh	Enable SSH transport support

libgpg-error

common-lisp	Install common-lisp files

libgpiod

tools	Build some useful gpio tools that use libgpiod.

libgpuarray

cuda	Enable NVIDIA CUDA toolkit support
opencl	Enable OpenCL support

libgweather

glade	Installs catalog files for dev-util/glade

libical

glib	Enable dev-libs/glib interface support

libisoburn

external-filters	Allow the use of external processes as file content filters (Note: this is a potential security risk)
external-filters-setuid	Also allow the use of external setuid processes as file content filters (Note: this is a potential security risk)
frontend-optional	Use dev-tcltk/bwidget which is not strictly required for the frontend
launch-frontend	Enable the tcl gui for xorriso
launch-frontend-setuid	Enable the tcl gui for xorriso under setuid

libisofs

verbose-debug	Enable verbose debug messages

libjcat

gpg	Enable GPG verification support via app-crypt/gpgme
man	Generate and install man pages
pkcs7	Enable PKCS7 verification support via net-libs/gnutls

liblogging

rfc3195	Enables RFC 3195 protocol (aka syslog-reliable) support. If you don't know what this is, you don't need it!
stdlog	Enables liblogging's core component (think of it as a the next version of the syslog(3) API).

libmemcached

hsieh	Use Hsieh hash algorithm.
libevent	Use the libevent event loop interface.
sasl	Use sasl auth for communications.

libnfc

pcsc-lite	Enable NFC drivers that require pcsc-lite

libnl

doc	Install development documentation
python	Install experimental dev-lang/python bindings
utils	Install command line interface utils

liborcus

spreadsheet-model	Enable the spreadsheet model implementation
tools	Build various low-level parsers

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 (via app-arch/bzip2).
pcre16	Build PCRE library for 16 bit characters (e.g. UTF-16).
pcre32	Build PCRE library for 32 bit characters (e.g. UTF-32).
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 (via sys-libs/zlib).

libpcre2

bzip2	Add support for pcregrep command to search within bzip2-compressed files (via app-arch/bzip2).
pcre16	Build PCRE library for 16 bit characters (e.g. UTF-16).
pcre32	Build PCRE library for 32 bit characters (e.g. UTF-32).
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 (via sys-libs/zlib).

libpeas

glade	Install the glade catalog
python	Build support for loading dev-lang/python plugins

librdkafka

lz4	Enable support for Kafka's LZ4 compression based on KIP-57 (uses app-arch/lz4)

librelp

gnutls	Use GnuTLS
libressl	Use LibreSSL
openssl	Use OpenSSL

libressl

asm	Enables assembly

libsecp256k1

asm	Enable x86_64 assembly optimisation
ecdh	Enable ECDH shared secret computation
endomorphism	Enable endomorphism
experimental	Allow experimental USE flags
recovery	Enable ECDSA pubkey recovery module
schnorr	Enable Schnorr signature module
test-openssl	Enable OpenSSL comparison tests

libslz

tools	Install additional tools (zenc, zdec)

libsodium

asm	Enables assembly implementations
urandom	Use /dev/urandom instead of /dev/random

libspt

libtirpc	Build against net-libs/libtirpc for RPC support

libtasn1

valgrind	Enable usage of dev-util/valgrind in debug

libtermkey

demos	Install demos, which pulls in dev-libs/glib

libunibreak

doc	Install html API documentation.
man	Generate man pages with doxygen.

libverto

glib	Support event loops using dev-libs/glib
libev	Support event loops using dev-libs/libev
libevent	Support event loops using dev-libs/libevent
tevent	Support event loops using sys-libs/tevent

libvoikko

expvfst	Enable experimental features of VFST morphology backend
hfst	Enable HFST morphology backend

libxmlb

stemmer	Enable language stemming support

libzia

ftdi	Enable support for FTDI USB chips

libzip

mbedtls	Use net-libs/mbedtls as TLS provider

link-grammar

aspell	Adds support for app-text/aspell spell checker
hunspell	Adds support for app-text/hunspell spell checker

log4cplus

iconv	Use inconv for wchar_t <-> char conversions. See also log4cplus's unicode.txt documentation
working-c-locale	Use the C99 locale facilities for wchar_t <-> char conversions. See also log4cplus's unicode.txt documentation
working-locale	Use C++'s std::locale for wchar_t <-> char conversions. See also log4cplus's unicode.txt documentation

log4cxx

smtp	Offer SMTP support via net-libs/libesmtp

m17n-lib

X	Build the Graphical User Interface API and utilities
anthy	Enable support for app-i18n/anthy input method
athena	Enable the MIT Athena widget set (x11-libs/libXaw)
gd	Build API and utilities based on media-libs/gd. This flag is only meaningful if the X USE flag is also enabled
libotf	Use dev-libs/libotf to handle OpenType fonts
libxml2	Use dev-libs/libxml2 to parse XML

msgpack

boost	Enable boost support

nettle

asm	Support assembly hand optimized crypto functions (i.e. faster run time)

nss

cacert	Include root/class3 certs from CAcert (http://www.cacert.org/)
utils	Install utilities included with the library

ocl-icd

khronos-headers	Install Khronos OpenCL headers.

onigmo

combination-explosion-check	enable combination explosion check
crnl-as-line-terminator	enable CR+NL as line terminator

oniguruma

crnl-as-line-terminator	enable CR+NL as line terminator

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.
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

ctapi	Use CT-API for accessing Smartcard hardware
notify	Enable notifications
openct	Use dev-libs/openct (and CT-API) for accessing Smartcard hardware
pcsc-lite	Use sys-apps/pcsc-lite (and PC/SC API) for accessing Smartcard hardware
secure-messaging	Enable secure messaging

openssl

asm	Support assembly hand optimized crypto functions (i.e. faster run time)
bindist	Disable/Restrict EC algorithms (as they seem to be patented) -- note: changes the ABI
rfc3779	Enable support for RFC 3779 (X.509 Extensions for IP Addresses and AS Identifiers)
sslv2	Support for the old/insecure SSLv2 protocol -- note: not required for TLS/https
sslv3	Support for the old/insecure SSLv3 protocol -- note: not required for TLS/https
tls-heartbeat	Enable the Heartbeat Extension in TLS and DTLS

openssl-compat

asm	Support assembly hand optimized crypto functions (i.e. faster run time)
bindist	Disable/Restrict EC algorithms (as they seem to be patented) -- note: changes the ABI
rfc3779	Enable support for RFC 3779 (X.509 Extensions for IP Addresses and AS Identifiers)
sslv2	Support for the old/insecure SSLv2 protocol -- note: not required for TLS/https
sslv3	Support for the old/insecure SSLv3 protocol -- note: not required for TLS/https
tls-heartbeat	Enable the Heartbeat Extension in TLS and DTLS

pkcs11-helper

nss	Enable NSS crypto engine

poco

7z	Add Support for the 7z archive format
cppparser	Build and install a minimal C++ parser
crypto	Encryption and digital signing classes
data	Database abstraction layer to easily send/retrieve data to/from various databases
file2pagecompiler	Utility to convert ordinary files to Page Compiler source files
json	Add JSON support
mariadb	Prefer dev-db/mariadb-connector-c over dev-db/mysql-connector-c
mongodb	Add dev-db/mongodb support
net	Classes to write network clients & servers
pagecompiler	Simple compiler translating HTML pages containing embedded C++ code into HTTPRequestHandler classes
pocodoc	POCO documentation generator
util	Several utility classes (like logger, timer, config file parser)
zip	Add support for the zip & gz archive formats

ppl

cdd	Build the ppl_lcdd program for vertex/facet enumeration accepting the same input format as the programs shipped with sci-libs/cddlib and sci-libs/lrslib
lpsol	Build the ppl_lpsol linear program solver that uses sci-mathematics/glpk for its input routines

rocr-runtime

non-free	Enables HSA image support using dev-libs/hsa-ext-rocr

serdisplib

tools	Build optional tools.

softhsm

gost	Enable gost algorithm
migration-tool	Build db migration tool

starpu

cuda	Enable NVIDIA CUDA toolkit support
gcc-plugin	Enable GCC extension plugin (experimental)
opencl	Enable OpenCL support
spinlock-check	Enable spinlock check
valgrind	Enable dev-util/valgrind support

stp

python	Enable building the Python interface

tinyxml

stl	Compile with TIXML_USE_STL support

tntnet

server	Enable tntnet server daemon

totem-pl-parser

archive	Enables ISO detection with app-arch/libarchive
crypt	Support AmazonAMZ decoding with dev-libs/libgcrypt
quvi	Use media-libs/libquvi for parsing video links

tvision

gpm	Support text mode mouse through sys-libs/gpm

ucommon

socks	Build with socks proxy support

userspace-rcu

regression-test	Run regression tests (requires FEATURES=test)

ustr

ustr-import	Install ustr-import developer program and source code for bundling.

weston

desktop	Enable the desktop shell
drm	Enable drm compositor support
editor	Install wayland-editor example application
fbdev	Enable fbdev compositor support
fullscreen	Enable fullscreen/kiosk shell
gles2	Use GLESv2 cairo instead of full GL
headless	Headless backend and a noop renderer, mainly for testing purposes
ivi	Enable the IVI shell
launch	Install weston-launch utility
pipewire	Enable virtual remote output with Pipewire on DRM backend
rdp	Enable Remote Desktop Protocol compositor support
remoting	Enable plugin to stream output to remote hosts using media-libs/gstreamer
resize-optimization	Increase performance, allocate more RAM. Recommended to disable on Raspberry Pi
screen-sharing	Enable screen-sharing through RDP
wayland-compositor	Enable Wayland compositor support
xwayland	Enable ability support native X11 applications

xapian

brass	Enabled brass backend db support
chert	Enabled chert backend db support
inmemory	Enabled inmemory backend db support
remote	Enabled remote 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)
threads	Enable threading support through pthread (or other libraries on AIX, IRIX, HPUX, Solars). Highly recommended

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

yaz

ziffy	Install ziffy, a promiscuous Z39.50 APDU sniffer

dev-lisp

clisp

hyperspec	Use local hyperspec instead of online version
svm	Build CLISP with support for the Support Vector Machine module

clx

doc	Builds documentation

cmucl

X	Build CLX, CLM, or Hemlock
doc	Installs package documentation
source	Include source code for CMUCL in installation

ecls

gengc	Use generational garbage collection (experimental)
libatomic	Use dev-libs/libatomic_ops library
precisegc	Use type information during garbage collection (experimental)

gcl

ansi	Build a GCL with ANSI support (else build a traditional CLtL1 image)
athena	Build xgcl - an interface to x11-libs/libXaw

sbcl

pax_kernel	Enable if the user plans to run the package under a pax enabled hardened kernel

dev-lua

lua-cjson

internal-fpconv	Enable internal number conversion routines, can increase overall performance by up to 50%

luarocks

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

dev-ml

cairo-ocaml

pango	Enable support for x11-libs/pango

csv

lwt	Enables the Lwt-based library for asynchronous operations.

dose3

parmap	Adds multi-core CPU support via dev-ml/parmap.
rpm4	Adds support for handling rpm4 files.
zip	Adds support for handling zip files.

eliom

ppx	Enable PPX syntax extension support.

js_of_ocaml

camlp4	Build with camlp4 syntax extensions.
deriving	Enable dev-ml/deriving support for improving the type safety.
lwt	Enable dev-ml/lwt support.
ppx	Enables the ppx syntax extension
react	Enable functionnal reactive programming support.

lablgtk

glade	Enable libglade bindings compilation.
gnomecanvas	Enable libgnomecanvas bindings compilation.
sourceview	Enable GtkSourceView support

logs

cli	Enables the Logs_cli library that provides command line support for controlling Logs.
fmt	Enables the Logs_fmt reporter.
lwt	Enables the Logs_lwt library that provides Lwt logging functions.

lwt

camlp4	Enable camlp4 syntax extension
libev	Enable the dev-libs/libev-based backend.
ppx	Enables the ppx syntax extension

ocaml-cohttp

async	Enables support for the dev-ml/async asynchronous execution library.
lwt	Enables support for the dev-ml/lwt cooperative light-weight thread library.

ocaml-cstruct

async	Support for asynchronous execution
lwt	Enable threads via lwt
ppx	Enable the ppx syntax extension

ocamlnet

httpd	Enables net-httpd web server component
zip	Enables netzip support to read/write gzip data using object channels

pgocaml

camlp4	Enable PG'Ocaml syntax extension.

tyxml

camlp4	Enables the camlp4 syntax extension (deprecated)
ppx	Enables the ppx syntax extension (preferred)

uutf

utftrip	Builds and install the utftrip executable: Among other things, reads unicode on stdin and rewrites it on stdout.

zarith

mpir	Use MPIR library instead of GMP.

dev-perl

App-Nopaste

browser	Spawn browser with pasted page
clipboard	copying of URLs with -x/--copy
gitlab	Ensure git is installed for reading/passing GitLab authentication
pastebin	pastebin.com support

Boulder

genbank	Provide support with Boulder::Genbank for decoding Genbank data records
store	Provide support with Boulder::Store for persisting Stone objects

Business-ISBN

barcode	Install dev-perl/GD-Barcode for rendering ISBN numbers as barcodes

Config-Any

conf	Install dev-perl/Config-General to support decoding .conf/.cnf files
ini	Install dev-perl/Config-Tiny to support decoding INI config files
json	Install support libraries to support decoding JSON config files
xml	Install support libraries to support decoding XML config files
yaml	Install support libraries to support decoding YAML config files

Convert-UUlib

system-uulib	Use dev-libs/uulib instead of bundled version.

Cookie-Baker

xs	Install dev-perl/Cookie-Baker-XS for accelerated performance

Coro

ev	Build support for using dev-perl/EV as an event-loop via Coro::EV
event	Build support for using dev-perl/Event as an event-loop via Coro::Event

DBD-MariaDB

mariadb	Use dev-db/mariadb-connector-c as the client library
mysql	Use dev-db/mysql-connector-c as the client library

DBD-SQLite

system-sqlite	Use the system-wide dev-db/sqlite installation

DBD-mysql

mariadb	Use dev-db/mariadb-connector-c as the client library
mysql	Use dev-db/mysql-connector-c as the client library
ssl	Compile in support for SSL connections via libmysqlclient

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

File-HomeDir

xdg	Ensure XDG Semantics for returned paths via x11-misc/xdg-user-dirs

File-Which

pwhich	Install dev-perl/App-pwhich which used to be a part of this package

GD

animgif	Enable animated gif support
fcgi	Build for FastCGI compatibility via dev-libs/fcgi instead of using PerlIO

Graphics-ColorNames

recommended	Install recommended support modules

HTML-Mason

modperl	Enable www-apache/mod_perl support

HTTP-Entity-Parser

xs	Install C-Based dependieces for faster performance

JSON

xs	Install C-based dev-perl/JSON-XS for faster performance

JSON-MaybeXS

xs	Install a C-Based backend to make JSON encode/decode fast

Lab-VXI11

libtirpc	Build against net-libs/libtirpc for RPC support

List-MoreUtils

xs	Install C-Based backend implementation for performance

MCE

sereal	Install dev-perl/Sereal-Encoder and decoder for faster worker IPC

Mail-IMAPClient

md5	Install support for DIGEST-MD5 and CRAM-MD5 Authentication
ntlm	Install support for NTLM Authentication
ssl	Install support for SSL Connections
zlib	Install support for COMPRESS DEFLATE connections

Net-SSH2

gcrypt	Use libgcrypt instead of openssl

PDL

badval	Enable bad values support
hdf	Enable HDF (version 4) format support
netpbm	Enable NETPBM and MPEG support
pdl2	Build pdf2 shell (requires Devel-REPL)
pgplot	Enable PGPLOT plotting capabilities

Ref-Util

xs	Install C-Based dev-perl/Ref-Util-XS for accelerated performance

Sub-Name

suggested	Install extra dependencies needed for extended regression tests

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

Test-Warnings

suggested	Install optional dependencies for extra tests

Text-CSV

xs	Install dev-perl/Text-CSV_XS for accelerated decoding

WWW-Form-UrlEncoded

xs	Install C-Based dependieces for faster performance

perl-headers

debug	Add source locations in generated .ph files to assist with debugging when errors occur
sizeof-warning	Include logic to warn when a .ph file tries to use a sizeof() that is unknown

dev-php

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_Beautifier

cli	Require dev-lang/php to be built with the "cli" SAPI and install the php_beautifier script.

agavi

executable	Install the "agavi" executable used to manage projects. This requires dev-php/phing, and may be omitted if you are (for example) deploying an existing site to a production server.

maxmind-db-reader

extension	Build the C extension that uses dev-libs/libmaxminddb

pecl-apcu

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-event

extra	Add support of the Libevent extra API

pecl-memcached

igbinary	Enable support for the igbinary serializer
json	Enable support for json serialization

pecl-redis

igbinary	Enables igbinary serialisation support
json	Enables json serializer support

pecl-zmq

czmq	Use the czmq high level bindings

phing

zip	Support zip archives by requiring said support in dev-lang/php.

swoole

http2	Add support for HTTP/2 protocol via net-libs/nghttp2

dev-python

PyQt5

bluetooth	Build bindings for the QtBluetooth module
dbus	Build bindings for the QtDBus module
declarative	Build bindings for the QtQml/QtQuick modules and enable the qmlscene plugin
designer	Build bindings for the QtDesigner module and enable the designer plugin
gui	Build bindings for the QtGui module
help	Build bindings for the QtHelp module
location	Build bindings for the QtLocation module
multimedia	Build bindings for the QtMultimedia module
network	Build bindings for the QtNetwork module
networkauth	Build bindings for the QtNetworkAuth module
opengl	Build bindings for the QtOpenGL module
positioning	Build bindings for the QtPositioning module
printsupport	Build bindings for the QtPrintSupport module
sensors	Build bindings for the QtSensors module
serialport	Build bindings for the QtSerialPort module
sql	Build bindings for the QtSql module
svg	Build bindings for the QtSvg module
testlib	Build bindings for the QtTest module
webchannel	Build bindings for the QtWebChannel module
webkit	Build bindings for the QtWebKit module
websockets	Build bindings for the QtWebSockets module
widgets	Build bindings for the QtWidgets module
x11extras	Build bindings for the QtX11Extras module
xmlpatterns	Build bindings for the QtXmlPatterns module

PythonQt

extensions	Install extensions

QtPy

designer	Build bindings for the QtDesigner module and enable the designer plugin
gui	Build bindings for the QtGui module
svg	Build bindings for the QtSvg module
testlib	Build bindings for the QtTest module
webengine	Build bindings for the QtWebEngine module

cryptography

idna	enable support for the old, deprecated IDNA specification (RFC 3490)

ctypescrypto

gost	Build with support for GOST Message Authentication Code

cvxopt

dsdp	Use interior point library sci-libs/dsdp
glpk	Use GNU Linear Programming Kit sci-mathematics/glpk

dap

server	Enable OpenDAP server support

dask

distributed	Add support for distributed computing with dev-python/distributed

drf-yasg

validation	Enable swagger spec validation using swagger-spec-validator

editorconfig-core-py

cli	Install command line interface as well as python library

falcon

cython	Build cython-based python modules

fastparquet

brotli	Enable support for brotli compression

glance_store

cinder	enable cinder backend supprt
swift	enable swift backend supprt
vmware	enable vmware backend supprt

gmpy

mpir	Use sci-libs/mpir as gmp implementation

icalendar

doc	Generate examples and other extra documentation

ipython

matplotlib	Add support for dev-python/matplotlib
nbconvert	Enable support for converting notebooks to various formats using app-text/pandoc
notebook	Install requirements for the web notebook based on www-servers/tornado

jira

jirashell	Include dependencies for jirashell (ipython, oauthlib)
kerberos	Support Kerberos authentication
oauth	Support OAuth authentication

kombu

mongodb	Enables MongoDB backend
msgpack	Enables MessagePack (de)serializer for Python
redis	Enables Redis backend
sqs	Enables Amazon SQS transport module for Kombu
yaml	Enables yaml backend

markdown

pygments	Enable fancy pygments support

matplotlib

excel	Pull dev-python/xlwt for the exceltools toolkit
gtk2	Enable x11-libs/gtk+:2 support
gtk3	Enable x11-libs/gtk+:3 support

matplotlib-python2

excel	Pull dev-python/xlwt for the exceltools toolkit
gtk3	Enable x11-libs/gtk+:3 support

mpmath

matplotlib	Add support for dev-python/matplotlib

msgpack

native-extensions	Compiles native "C" extensions (speedups, instead of using python fallback code).

nbdime

webtools	Install web-based diff and merge tools.

netaddr

cli	Enable netaddr shell with dev-python/ipython

networkx

extras	Provide graph drawing and graph layout algorithms along with shapefile format reading and writing
pandas	Provides a DataFrame, which is a tabular data structure with labeled axes
scipy	Enables scipy backend
yaml	Provides YAML format reading and writing

nltk-data

extra	Install the complete set of data files. Otherwise, only files required by tests are installed.

nose

coverage	Pull in dev-python/coverage needed for nose-xcover plugin.

numexpr

mkl	Enable support for Intel Vector Math Library, part of sci-libs/mkl.

pandas

full-support	Pull all packages to give pandas full support

paramiko

server	Enable server feature

passlib

bcrypt	bcrpyt hash algoryptm support
scrypt	accelerated scrypt algoythm support
totp	time based one time password support

paste

flup	enable support for flup (and therefore for various wgsi servers and middleware)
openid	enable OpenID support

pillow

imagequant	Build with Image Quantization Library support

py-amqp

extras	Install extra tools to generate initial Python mod from an AMQP XML file

pygame

midi	Enable midi support using media-libs/portmidi

pyglet

image	Enable support for image formats other than PNG and BMP

pygpu

cuda	Enable NVIDIA CUDA toolkit support
opencl	Enable OpenCL support

pyilmbase

numpy	Add bindings for dev-python/numpy use.

pyocr

cuneiform	Enable support for the app-text/cuneiform OCR engine
tesseract	Enable support for the app-text/tesseract OCR engine

pypax

ptpax	Enable PT_PAX_FLAGS support.
xtpax	Enable XATTR_PAX_FLAGS support.

pypy-exe

low-memory	Build using PyPy with the engine configured towards low memory footprint. This makes it possible to build PyPy using ~3.5G of RAM on amd64 and ~half of that on x86, at the cost of lengthened build time.

pypy3-exe

low-memory	Build using PyPy with the engine configured towards low memory footprint. This makes it possible to build PyPy using ~3.5G of RAM on amd64 and ~half of that on x86, at the cost of lengthened build time.

pyside2

3d	Build Qt3DCore, Qt3DAnimation, Qt3DExtras, Qt3DInput, Qt3DLogic, and Qt3DRender modules
charts	Build QtCharts module
concurrent	Build QtConcurrent module
datavis	Build QtDataVisualization module
designer	Build QtDesigner and QtUiTools modules
gles2-only	Build QtGui "QOpenGL*" classes
gui	Build QtGui module
help	Build QtHelp module
location	Build QtLocation module
multimedia	Build QtMultimedia and QtMultimediaWidgets modules
network	Build QtNetwork module
positioning	Build QtPositioning module
printsupport	Build QtPrintSupport module
qml	Build QtQml module
quick	Build QtQuick and QtQuickWidgets modules
script	Build QtScript module
scripttools	Build QtScriptTools module
scxml	Build QtScxml module
sensors	Build QtSensors module
speech	Build QtTextToSpeech module
sql	Build QtSql module
svg	Build QtSvg module
testlib	Build QtTest module
webchannel	Build QtWebChannel module
webengine	Build QtWebEngine and QtWebEngineWidgets modules
websockets	Build QtWebSockets module
widgets	Build QtWidgets module
x11extras	Build QtX11Extras module
xml	Build QtXml module
xmlpatterns	Build QtXmlPatterns module

python-mpd

twisted	Enable twisted support

python-stdnum

vies	Enable VIES

pyudev

qt5	Install PyQt5 bindings

pyyaml

libyaml	enable support for C implementation using libyaml

pyzmq

draft	Enable draft API support

rarfile

compressed	Enables the module to support compressed v3 archives by calling the app-arch/unrar.

rdflib

redland	enable support for Redland triplestore

restkit

cli	Install the restcli command line interface/tool, based on dev-python/ipython

rfc3986

idna	enable support for the IDNA specification (RFC 5891)

shiboken2

docstrings	Expose documentation as Python docstrings (recommended)
numpy	Implicitly convert passed NumPy arrays to Qt lists
vulkan	Generate "QSurface::VulkanSurface" bindings

simplespectral

faster	Use sci-libs/scipy to speed up drawing
fastest	Use dev-python/pyFFTW to speed up drawing to the max

socketpool

eventlet	Install dev-python/eventlet as needed for the eventlet backend.
gevent	Install dev-python/gevent as needed for the gevent backend.

sphinx

net	enable internet capabilities

sympy

imaging	Add support for dev-python/pillow
ipython	Add support for dev-python/ipython
mathml	Add support for mathml
pyglet	Use dev-python/pyglet for plots and print preview
symengine	Add support for a dev-python/symengine backend
texmacs	Add app-office/texmacs interface
theano	Add support for dev-python/theano

tappy

yaml	Pull dependencies needed to support YAML blocks associated with test results.

tinyrpc

gevent	Add support for gevent
httpclient	Add support for httpclient
jsonext	Add support for jsonext
websocket	Add support for websocket
wsgi	Add support for wsgi
zmq	Add support for zmq

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
subtitles	Support conversion between po and sub files
yaml	Support YAML format

twisted

conch	include Twisted SSHv2 implementation
http2	include http2 support
serial	include serial port support

urllib3

brotli	Enable support for brotli compression

ws4py

client	Install client modules
server	Install server modules

wxpython

examples	Install interactive demo module browser and sample applets.

zeep

async	Add async support
tornado	Add tornado support

dev-qt

designer

declarative	Build the qdeclarativeview plugin
webkit	Build the qwebview plugin

linguist-tools

qml	Enable QML support in lupdate

qdoc

qml	Enable QML/JS parsing support

qt-creator

android	Build plugin for Android devices
autotest	Enable integration with popular unit testing frameworks (QtTest, Google Test, Boost.Test)
autotools	Enable autotools project manager plugin
baremetal	Build plugin for bare metal devices
beautifier	Build the beautifier plugin (supports astyle, clang-format, and uncrustify)
boot2qt	Build plugin for Boot2Qt devices
clang	Build clang-based plugins (code model, formatting, refactoring, static analysis)
clearcase	Add support for IBM ClearCase version control system (requires manual installation of ClearCase client)
cmake	Enable cmake project manager plugin
cppcheck	Enable integration with dev-util/cppcheck
ctfvisualizer	Build the Chrome Trace Format visualizer plugin
designer	Enable designer for QtWidgets-based UIs
glsl	Enable GLSL editor
help	Enable the integrated documentation viewer
ios	Build plugin for Apple iOS devices
lsp	Add support for the Language Server Protocol (LSP)
mcu	Build plugin for MCU devices
mercurial	Add support for dev-vcs/mercurial version control system
modeling	Enable graphical model editor
nim	Build plugin for Nim language support
perforce	Add support for Perforce version control system (requires manual installation of Perforce client)
perfprofiler	Build the Linux Perf-based profiler plugin
python	Build plugin for Python language support
qbs	Enable QBS project manager plugin
qmldesigner	Enable designer for QML/QtQuick-based UIs
qmlprofiler	Build the QML profiler plugin
qnx	Build plugin for QNX devices
remotelinux	Add support for deployment and execution on a remote Linux host
scxml	Enable graphical SCXML editor
serialterminal	Build serial terminal plugin
silversearcher	Enable integration with sys-apps/the_silver_searcher
systemd	Add support for retrieving application output from journald
valgrind	Enable integration with dev-util/valgrind
webassembly	Build WebAssembly plugin
webengine	Use dev-qt/qtwebengine to view documentation
winrt	Build plugin for WinRT devices

qt-docs

3d	Install documentation for dev-qt/qt3d
assistant	Install documentation for dev-qt/assistant
bluetooth	Install documentation for dev-qt/qtbluetooth
charts	Install documentation for dev-qt/qtcharts
concurrent	Install documentation for dev-qt/qtconcurrent
core	Install documentation for dev-qt/qtcore
datavis	Install documentation for dev-qt/qtdatavis3d
declarative	Install documentation for dev-qt/qtdeclarative
designer	Install documentation for dev-qt/designer
gamepad	Install documentation for dev-qt/qtgamepad (available in qt overlay only)
graphicaleffects	Install documentation for dev-qt/qtgraphicaleffects
gui	Install documentation for dev-qt/qtgui
help	Install documentation for dev-qt/qthelp
html	Install documentation in HTML format
imageformats	Install documentation for dev-qt/qtimageformats
linguist	Install documentation for dev-qt/linguist
location	Install documentation for dev-qt/qtlocation
multimedia	Install documentation for dev-qt/qtmultimedia
network	Install documentation for dev-qt/qtnetwork
networkauth	Install documentation for dev-qt/qtnetworkauth
positioning	Install documentation for dev-qt/qtpositioning
printsupport	Install documentation for dev-qt/qtprintsupport
qch	Install documentation in QCH format
qdoc	Install documentation for dev-qt/qdoc
quickcontrols	Install documentation for dev-qt/qtquickcontrols
quickcontrols2	Install documentation for dev-qt/qtquickcontrols2
script	Install documentation for dev-qt/qtscript
scxml	Install documentation for dev-qt/qtscxml
sensors	Install documentation for dev-qt/qtsensors
serialbus	Install documentation for dev-qt/qtserialbus
serialport	Install documentation for dev-qt/qtserialport
speech	Install documentation for dev-qt/qtspeech
sql	Install documentation for dev-qt/qtsql
virtualkeyboard	Install documentation for dev-qt/qtvirtualkeyboard
webchannel	Install documentation for dev-qt/qtwebchannel
webengine	Install documentation for dev-qt/qtwebengine
websockets	Install documentation for dev-qt/qtwebsockets
webview	Install documentation for dev-qt/qtwebview
widgets	Install documentation for dev-qt/qtwidgets
x11extras	Install documentation for dev-qt/qtx11extras
xmlpatterns	Install documentation for dev-qt/qtxmlpatterns

qt3d

gamepad	Add support for gamepad hardware via dev-qt/qtgamepad
qml	Build QML/QtQuick bindings

qtbluetooth

qml	Build QML/QtQuick bindings and imports

qtcharts

qml	Build QML/QtQuick bindings and imports

qtcore

old-kernel	Disable syscalls not available on Linux kernels older than 3.17
systemd	Enable native journald logging support

qtdatavis3d

qml	Build QML/QtQuick bindings and imports

qtdeclarative

localstorage	Build the LocalStorage import for QtQuick (requires QtSql)
vulkan	Enable support for Vulkan
widgets	Enable QtWidgets support

qtdiag

network	Report network information
widgets	Report widget style information

qtgamepad

evdev	Enable support for input devices via evdev
qml	Build QML bindings

qtgui

egl	Enable EGL integration
eglfs	Build the EGL Full Screen/Single Surface platform plugin
evdev	Enable support for input devices via evdev
ibus	Build the IBus input method plugin
libinput	Enable support for input devices via dev-libs/libinput
tslib	Enable support for touchscreen devices via x11-libs/tslib
tuio	Build plugin to receive touch events over the TUIO protocol
vulkan	Enable support for Vulkan
wayland	Provide dev-qt/qtwayland to ensure Qt applications can be run as Wayland clients

qtmultimedia

gstreamer	Enable audio support via media-libs/gstreamer using SLOT 1.0
qml	Build QML/QtQuick bindings and imports
widgets	Build the QtMultimediaWidgets module

qtnetwork

bindist	Disable EC support via dev-libs/openssl
connman	Enable net-misc/connman-based bearer plugin
gssapi	Enable support for GSSAPI (virtual/krb5)
libproxy	Use net-libs/libproxy for automatic HTTP/SOCKS proxy configuration
networkmanager	Enable net-misc/networkmanager-based bearer plugin

qtpositioning

geoclue	Use enhanced location information from app-misc/geoclue
qml	Build QML bindings

qtquickcontrols

widgets	Enable QtWidgets support

qtquickcontrols2

widgets	Enable QtWidgets support

qtscript

scripttools	Build the QtScriptTools module (requires QtWidgets)

qtsensors

qml	Build QML bindings

qtvirtualkeyboard

handwriting	Adds handwriting recognition integration support

qtwayland

vulkan	Enable support for Vulkan-based server buffer integration

qtwebchannel

qml	Build QML/QtQuick bindings and imports

qtwebengine

designer	Install the QWebEngineView plugin used to add widgets in dev-qt/designer forms that display web pages.
geolocation	Enable physical position determination via dev-qt/qtpositioning
jumbo-build	Combine source files to speed up build process.
system-ffmpeg	Use the system-wide media-video/ffmpeg instead of bundled.
system-icu	Use the system-wide dev-libs/icu instead of bundled.
widgets	Enable QtWidgets support

qtwebkit

geolocation	Enable physical position determination via dev-qt/qtpositioning
gstreamer	Enable HTML5 audio/video support via media-libs/gstreamer using SLOT 1.0
hyphen	Enable hyphenation support via dev-libs/hyphen
multimedia	Enable HTML5 audio/video support via dev-qt/qtmultimedia
orientation	Enable device orientation detection via dev-qt/qtsensors
printsupport	Enable printing via dev-qt/qtprintsupport
qml	Build QML/QtQuick bindings

qtwebsockets

qml	Build QML bindings

qtxmlpatterns

qml	Build the XmlListModel import for QtQuick (requires QtDeclarative)

dev-ros

rosbag

lz4	Add support for lz4 compressed bags.

rosconsole

glog	Use dev-cpp/glog as log backend.
log4cxx	Use dev-libs/log4cxx as log backend.

dev-ruby

barby

cairo	Add support for writing images (PNG, PS, EPS and, if supported, PDF and SVG) using dev-ruby/rcairo. Not available on JRuby.
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.

faraday_middleware

mashify	Include FaradayMiddleware::Mashify
oauth	Include FaradayMiddleware::OAuth
parsexml	Include FaradayMiddleware::ParseXml
rashify	Include FaradayMiddleware::Rashify

maruku

highlight	Enable source code highlighting via dev-ruby/syntax

mysql2

mariadb	Use mariadb bindings

net-ssh

ed25519	Use dev-ruby/ed25519 for Ed25519 support
sodium	Use dev-libs/libsodium via dev-ruby/rbnacl for Ed25519 support

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.

rrdtool-bindings

graph	Enable support for graphing functions

rspec-core

highlight	Enable source code highlighting via dev-ruby/coderay

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

gauche

mbedtls	Enable support for net-libs/mbedtls

gauche-gl

cg	Enable NVidia Cg binding

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
networking	Include networking interfaces
regex	Include regular expression interfaces

kawa

awt	Assume AWT is available
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 Java servletapi
swing	Assume Swing is available
xqtests	Support XQuery Test Suite

racket

futures	Enable racket/future library for fine-grained hardware parallelism
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.
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.
libscm	Build and install libscm.a and related headers
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.

slib

gambit	Support for gambit scheme implementation
scm	Support for scm scheme implementation

dev-tcltk

expect-lite

debug	pull in packages needed for runtime interactive debugger

tcl3d

ode	Enable support for physics engine from dev-games/ode
osg	Enable support for 3D toolkit from dev-games/openscenegraph

tktreectrl

shellicon	shellicon extension

dev-tex

abntex

lyx	Install with app-office/lyx layout

biblatex

biber	Install the unicode compatible backend processor

circuit_macros

script	Install cm2pdf to automatically create a correctly sized PDF from a circuit_macro m4 source

dot2texi

pgf	Enable support for dev-tex/pgf (The TeX Portable Graphic Format)
pstricks	Enable pstricks support

pythontex

highlighting	Syntax highlighting using dev-python/pygments

dev-texlive

texlive-basic

luajittex	Add support for LuaJitTeX: LuaTeX based on LuaJIT which is usually faster.

dev-util

android-ndk

legacy-toolchains	Install legacy toolchains
target-32	Support for 32-bit targets
target-64	Support for 64-bit targets

android-studio

custom-jdk	Install and use Android Studio's custom JRE.

anjuta

devhelp	Enable devhelp integration
glade	Build glade plugin for anjuta
packagekit	Use packagekit to search for missing tools
terminal	Enable terminal plugin based on x11-libs/vte

bazel

tools	Install extra bazel tools to build from sources

bitcoin-tx

knots	Build enhanced Bitcoin Knots version, rather than Bitcoin Core

buildbot

docker	Add support for worker docker command steps
irc	Add support for status delivery through an ircbot.

bustle

interactivetests	Build interactive test programs
threaded	Build with support for multithreaded execution.

catalyst

ccache	Enables ccache support
iso	Pulls in the depends for building iso images
system-bootloader	Pulls in the depends needed to setup livecd bootloader from the host system rather than using a cdtar

cccc

apidoc	Build software docs with doxygen/graphviz and metrics with cccc
mfc	Add patch for MFC dialect options

clion

custom-jdk	Install and use IntelliJ's custom JRE.

cmake

system-jsoncpp	Use system copy of dev-libs/jsoncpp instead of bundled one.

coccigrep

vim	Install the coccigrep vim plugin

codeblocks

contrib	Build additional contrib components
fortran	Build FortranProject plugin which enables to use Code::Blocks IDE for Fortran language

cppcheck

htmlreport	install cppcheck-htmlreport

ctags

json	Enable JSON output support
xml	Enable XML parsing support
yaml	Enable YAML parsing support

cutter

jupyter	Add support for jupyter notebook
webengine	Use dev-qt/qtwebengine for in-app jupyter browser

cwdiff

a2ps	install app-text/a2ps for postscript output
mercurial	install hg wdiff alias for dev-vcs/mercurial

devhelp

gedit	Install plugin for app-editors/gedit

dialog

minimal	Disable library, install command-line program only

diffoscope

R	Use dev-lang/R
binutils	Use sys-devel/binutils
cpio	Use app-arch/cpio
diff	Use sys-apps/diffutils
docx	Use app-text/docx2txt
dtc	Use sys-apps/dtc
e2fsprogs	Use sys-fs/e2fsprogs
file	Use sys-apps/file
find	Use sys-apps/findutils
gettext	Use sys-devel/gettext
gpg	Use app-crypt/gnupg
haskell	Use dev-lang/ghc
hdf5	Use sci-libs/hdf5
hex	Use app-editors/vim-core
iso	Use virtual/cdrtools
llvm	Use sys-devel/llvm
opendocument	Use app-text/odt2txt
pascal	Use dev-lang/fpc
rpm	Use app-arch/rpm
squashfs	Use sys-fs/squashfs-tools
ssh	Use net-misc/openssh
tar	Use app-arch/tar
tcpdump	Use net-analyzer/tcpdump
xz	Use app-arch/xz-utils
zip	Use app-arch/unzip

edb-debugger

jumbo-build	Experimental jumbo (also known as unity) build capability

edi

clang	Provide integration with sys-devel/clang for autocompletion and inline errors

emilpro

system-binutils	Use the gentoo binutils instead of building against an unpatched vanilla version

geany

gtk3	Use GTK+3 instead of GTK+2
vte	Enable Terminal support (x11-libs/vte)

geany-plugins

ctags	Enable ctags plugin
debugger	Enable the debugger plugin which interfaces with sys-devel/gdb
enchant	Enable spell checking using enchant
gpg	Enable geanypg plugin which integrates GPG using app-crypt/gpgme
gtk3	Use GTK+3 instead of GTK+2
gtkspell	Use gtkspell for dictionary support in GeanyVC
markdown	Enable the markdown plugin
pretty-printer	Enable pretty-printer plugin
scope	Enable the scope plugin which is a graphical GDB front-end
soup	Enable updatechecker and geniuspaste plugins which require net-libs/libsoup
workbench	Enable workbench plugin

glade

webkit	Build catalog support for net-libs/webkit-gtk:4 widgets.

global

vim	Integrate the GNU GLOBAL source code tag system with Vim

gnome-builder

clang	Provide integration with sys-devel/clang for best possible C/C++ autocompletion, semantic highlighting, symbol resolving, and diagnostics support
devhelp	Provide API docs browsing and integration via dev-util/devhelp
git	Provide support for the Git version control system via dev-libs/libgit2-glib (such as setup of Git for New Project, direct cloning for Open Project and changed lines indicators in the editor gutter)
glade	Provide integration with dev-util/glade UI designer for Gtk
sysprof	Provide an integrated profiler via dev-util/sysprof
vala	Provide an autoindenter, autocompletion, diagnostics, and symbol resolver for Vala

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.
optimisememory	To build libtcmalloc with smaller internal caches.

gtk-doc

highlight	Enable source code highlighting
vim	Enable source code highlighting through app-editors/vim

heaptrack

gui	Install Qt5-based analyzer tool

idea-community

jbr11	Install and use the Java 11 based version of JetBrains Runtime.
jbr8	Install and use the Java 8 based version of JetBrains Runtime.

intel-ocl-sdk

android	Install android related files
system-boost	Use system boost (dev-libs/boost) instead of bundled one
system-clang	Use system clang (sys-devel/clang) instead of bundled one
system-tbb	Use system Thread Building Blocks (dev-cpp/tbb) instead of bundled one
tools	Install Intel Offline Compiler

kdevelop

gdbui	Enable GUI for attaching GDB to a running process
hex	Enable hex editor plugin via app-editors/okteta
qmake	Enable support for QMake build system
reviewboard	Enable reviewboard support
webkit	Enable deprecated dev-qt/qtwebkit instead of dev-qt/qtwebengine for integrated documentation

kernelshark

custom-optimization	Build with user-specified compiler optimizations (-Os, -O0, -O1, -O2, -O3) from CFLAGS

ltrace

unwind	Use sys-libs/libunwind for frame unwinding support

lttng-tools

ust	Support LTTng-UST (Userspace Tracing)

lttng-ust

numa	Enable numa support

massif-visualizer

callgraph	Enable detailed snapshot analysis using media-gfx/kgraphviewer

mdds

valgrind	Add support for memory debugging using dev-util/valgrind

mingw64-runtime

idl	Install idl files.
libraries	Build extra libraries: mangle, pseh, winpthreads.
secure-api	Expose secure API (*_s function) by default.
tools	Build extra tools: gendef, genidl.

molecule

plugins	Add plugins provided by dev-util/molecule-plugins

nemiver

memoryview	Enable the optional hexadecimal memory inspection with app-editors/ghex

nvidia-cuda-sdk

cuda	Build CUDA binaries
opencl	Build OpenCL binaries

nvidia-cuda-toolkit

debugger	Installs the CUDA debugger
eclipse	Install plugins for eclipse
profiler	Installs the NVIDIA CUDA visual profiler

ostree

archive	Use libarchive
dracut	Install dracut module
grub	Enable grub configuration generator
http2	Use http2
httpd	Enable ostree trivial-httpd entrypoint
libmount	Use libmount
soup	Use libsoup for networking

perf

clang	Enable builtin clang and LLVM support
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.
numa	Enable NUMA support
perl	Add support for Perl as a scripting language for perf tools.
systemtap	Add support to define SDT event in perf tools.
unwind	Use sys-libs/libunwind for frame unwinding support.

pkgconf

pkg-config	Install as a replacement for dev-util/pkgconfig

pkgconfig

internal-glib	Use internal copy of dev-libs/glib

pycharm-community

bundled-jdk	Use bundled jdk

pycharm-professional

bundled-jdk	Use bundled jdk

scanmem

gui	Enable the GameConqueror GUI

sccache

azure	Enable Azure Blob Storage support
dist-client	Enables distributed support in the sccache client
dist-server	Enables the sccache-dist binary
gcs	Enable Google Cloud Storage support
redis	Enable Redis support
s3	Enable Amazon S3 support

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
zfs	Enable support for chroots using ZFS shapshots/clones

spirv-llvm-translator

tools	Install the command-line translator llvm-spirv

strace

aio	Enable dev-libs/libaio support for tracing Asynchronous I/O operations
elfutils	Enable stack backtraces (-k flag) via dev-libs/elfutils
unwind	Enable stack backtraces (-k flag) via sys-libs/libunwind

sysdig

modules	Build kernel modules needed for tracing local events. Disable this only if you intend to use sysdig purely to work with dumpfiles.

systemtap

libvirt	Support probing of libvirt domains.

trace-cmd

udis86	Enable support for dev-libs/udis86 disassembler library

uftrace

capstone	Use capstone to provide dynamic tracing without recompilation

unrpyc

module	Build un.rpyc module for run-time decompiling
proto0	Use pickle protocol 0 for un-rpyc module. May be usefule for very old games
proto1	Use pickle protocol 1 for un-rpyc module. Default if no protocol is selected
proto2	Use pickle protocol 2 for un-rpyc module

vulkan-tools

cube	Build the cube/cubepp demos
vulkaninfo	Build the vulkaninfo utility

dev-vcs

cssc

valgrind	Enable usage of dev-util/valgrind in tests

cvs

server	Enable server support

cvs2svn

bazaar	Support for dev-vcs/bzr

cvsync

gcrypt	Use dev-libs/libgcrypt for hash functions.
mhash	Use app-crypt/mhash for hash functions.
openssl	Use dev-libs/openssl for hash functions.

darcs

diff	Use 'lcs' for diff building.
http	Use the pure Haskell HTTP package for HTTP support.
network-uri	Get Network.URI from the network-uri package.
terminfo	Use the terminfo package for enhanced console support.
threaded	Use threading and SMP support.

fossil

fusefs	Enable the Fuse Filesystem
json	Enable the JSON API of Fossil's wiki
legacy-mv-rm	Enable legacy behavior for mv/rm (skip checkout files).
miniz	Use the bundled miniz for compression instead of zlib. Incompatible with ssl.
system-sqlite	Use the system SQLite instead of the bundled one
tcl-private-stubs	Enable Tcl integration via private stubs mechanism
tcl-stubs	Enable Tcl integration via stubs library mechanism
th1-docs	Enable TH1 for embedded documentation pages
th1-hooks	Enable TH1 hooks for commands and web pages

git

blksha1	Use the new optimized SHA1 implementation
cgi	Install gitweb too
curl	Support fetching and pushing (requires webdav too) over http:// and https:// protocols
gpg	Pull in gnupg for signing -- without gnupg, attempts at signing will fail at runtime!
highlight	GitWeb support for app-text/highlight
mediawiki	Support pulling and pushing from MediaWiki
mediawiki-experimental	Add experimental patches for improved MediaWiki support
pcre-jit	Enable JIT for pcre
perforce	Add support for Perforce version control system (requires manual installation of Perforce client)
ppcsha1	Make use of a bundled routine that is optimized for the PPC arch
subversion	Include git-svn for dev-vcs/subversion support
tk	Include the 'gitk' and 'git gui' tools
webdav	Adds support for push'ing to HTTP/HTTPS repositories via DAV

git-annex

assistant	Enable git-annex assistant and watch command
benchmark	Enable benchmarking
concurrentoutput	Use concurrent-output library (experimental)
magicmime	Use libmagic to determine file MIME types
network-uri	Get Network.URI from the network-uri package.
pairing	Enable pairing of git annex repositories
s3	Enable Amazon S3 remote
torrentparser	Use haskell torrent library to parse torrent files
webapp	Enable git-annex webapp
webdav	Enable webdav remote

gitg

glade	Install a glade catalog file
python	Install Python bindings for those plugins requiring it.

gitolite

contrib	Install user-contributed files
tools	Install tools to e.g. convert a Gitosis config to gitolite or one to check if your setup is gitolite >= 3.x compatible

gitolite-gentoo

contrib	Install user-contributed files
tools	Install tools to e.g. convert a Gitosis config to gitolite or one to check if your setup is gitolite >= 3.x compatible

kdesvn

man	Build and install man pages

mercurial

chg	Support Mercurial command server client
gpg	Support signing with GnuPG.
tk	Install dev-lang/tk for hgk script.

subversion

ctypes-python	Build and install Ctypes Python bindings
dso	Enable runtime module search
extras	Install extra scripts (examples, tools, hooks)
http	Enable http support using net-libs/serf
kwallet	Enable encrypted storage of passwords with kde-frameworks/kwallet

games-action

beathazardultra

bundled-libs	Use the upstream provided bundled libraries.

chromium-bsu

mixer	Enables media-libs/sdl-mixer sound backend instead of media-libs/openal one.

d1x-rebirth

demo	Use the demo data instead of the full game
l10n_de	Provides German translations for the game's briefings, robot descriptions, and outro of the original campaign
music	Support for ingame music
opl3-musicpack	Include alternate version of the game's music, recorded with the Yamaha YMF262 OPL3 soundchip
sc55-musicpack	Include alternate version of the game's music, recorded with the Roland Sound Canvas SC-55 MIDI module

dxx-rebirth

data	Install data files
descent1	Install Descent 1 resources and executable
descent2	Install Descent 2 resources and executable
l10n_de	Provides German translations for the game's briefings, robot descriptions, and outro of the original campaign
music	Enable music support
opl3-musicpack	Include alternate version of the game's music, recorded with the Yamaha YMF262 OPL3 soundchip
sc55-musicpack	Include alternate version of the game's music, recorded with the Roland Sound Canvas SC-55 MIDI module
textures	Include high resolution (640x480) backgrounds, briefing images and fonts (Descent 1)

hotline-miami

bundled-libs	Use bundled libraries.
launcher	Install qt launcher

minetest

client	Build Minetest client
leveldb	Enable LevelDB backend
redis	Enable redis backend via dev-libs/hiredis
server	Build Minetest server
spatial	Enable SpatialIndex AreaStore backend

solar2

bundled-libs	Use the upstream provided bundled libraries.

supermariowar

server	Compile and install Super Mario War server files

supertuxkart

fribidi	Support for right-to-left languages
nettle	Use dev-libs/nettle crypto backend
recorder	Enable recording with media-libs/libopenglrecorder
wiimote	Support for wiimote input devices

swordandsworcery

bundled-libs	Use the upstream provided bundled libraries.

trine

launcher	Install GTK+ launcher

trine-enchanted-edition

launcher	Install GTK+ launcher

trine2

launcher	Install GTK+ launcher

games-arcade

bomns

editor	enables building the level editor

burgerspace

network	Enable client-server support

commandergenius

downloader	Allows some Keen games to be downloaded from the menu

jazz2

gles2-only	Use GLES 2.0 or later instead of full OpenGL 2.1
server	Build the multiplayer game server

jazz2-data

cc	Install The Christmas Chronicles additional data
demo	Use the free demo data instead of the full retail game data
gles2-only	Use GLES 2.0 or later instead of full OpenGL 2.1

jumpnbump

music	Enable playing of background music

lbreakout2

themes	Install additional themes

moleinvasion

music	Download and install the music files

oshu

osu-skin	Include more complete osu-skin (other is minimal)

performous

midi	Enable MIDI I/O support
songs	Install a few demo songs
tools	Enable building of song extraction utilities for SingStar and Guitar Hero
webcam	Enable Webcam support

savagewheels

fmod	Enable the fmod music and sound effects library

tuxanci

physfs	Use dev-games/physfs instead of dev-libs/libzip to load compressed data

games-board

cockatrice

client	Build with client
oracle	Build with oracle
server	Compile server support

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

pioneers

help	Enable gnome ingame help via scrollkeeper

pysolfc

extra-cardsets	Install extra cardsets
sound	Enable sound support using dev-python/pygame

spider

athena	Enable athena widgets

stockfish

general-32	Generic unoptimized 32-bits build
general-64	Generic unoptimized 64-bits build
optimize	Enable upstream -O3 optimizations (default enabled)

tablebase-syzygy

6-pieces	Install tablebases for 6 pieces (huge!)

teg

client	Compile the client
debug	Turn on debugging
ggz	Enable GGZ Gaming Zone support
robot	Compile the robot
server	Compile the server

xboard

default-font	Install the default font that xboard uses
zippy	Enable experimental zippy client

games-emulation

dolphin

discord-presence	Enables Discord Rich Presence, show the current game on Discord
egl	Enable EGL support
evdev	Enable evdev input support
log	Increase logging output
lto	Add support for link-time optimizations.

dosbox

core-inline	Enable memory-increasing inlines for better performance but requiring more build time
glide	Enable unofficial Glide emulation via media-libs/openglide

dosbox-staging

dynrec	Use recompiling cpu core instead of dynamic x86/x64 specific cpu core
opus	Support compressed audio tracks (.opus) used with CDROM images

fceux

logo	Enable the ability to add a logo screen when creating AVIs

generator

sdlaudio	Enable SDL Audio

hatari

capsimage	Use dev-libs/spsdeclib to read .IPF, .RAW, and .CTR disk images
microphone	Use media-libs/portaudio for Falcon microphone handling
portmidi	Use media-libs/portmidi as an alternative MIDI backend
sdl2	Use libsdl2 instead of libsdl

higan

icarus	Build icarus library manager
udev	Enable udev based input

m64py

7z	Ensure support for .7z archives.
rar	Ensure support for .rar archives.

mednafen

debugger	Build with internal debugger

mgba

discord	Enable Discord RPC support
elf	Enable the use of elf utils via dev-libs/elfutils

mupen64plus

audio-sdl	Enable SDL audio plugin.
input-sdl	Enable SDL input plugin.
rsp-hle	Enable HLE RSP plugin.
ui-console	Enable default console UI.
ui-m64py	Enable PyQt5 UI using games-emulation/m64py.
video-glide64mk2	Enable Glide64mk2 video plugin.
video-rice	Enable Rice video plugin.

mupen64plus-core

debugger	Build the debugger
new-dynarec	Enable new experimental dynamic recompiler implementation (only for x86 and arm)
opencv	Support video capture via media-libs/opencv
osd	Overlay emulator messages using on-screen-display

mupen64plus-video-glide64mk2

hires	Support hi-resolution textures (requires dev-libs/boost)

pcsxr

archive	Support compressed files (via libarchive)
ccdda	Support compressed CDDA (requires ffmpeg)
cdio	Use libcdio for CD support
sdl	Use SDL sound backend (other parts of SDL are used unconditionally)

ppsspp

headless	Build headless version of the PPSSPP
system-ffmpeg	Use the system-wide media-video/ffmpeg instead of bundled

snes9x

netplay	Enable playing ROMs over the network (not recommended)

vbam

link	Enable GBA linking functionality

zsnes

debug	Enable the builtin debugger

games-engines

devilutionx

lto	Build with link time optimization enabled

exult

sdl2	Use libsdl2 instead of libsdl

frobtads

tads2compiler	Build TADS2 compiler
tads3compiler	Build TADS3 compiler

odamex

client	Build client target
master	Build master server target (advertises odamex server list)
odalaunch	Build the wxWidgets based launcher
portmidi	Enable PortMidi support
server	Build server target

openmw

devtools	Install development tools like bsatool, esmtool and opencs.

renpy

development	Install IDE for game developers and an empty game template

residualvm

mpeg2	enable mpeg2 codec for cutscenes

scummvm

fluidsynth	compile with support for fluidsynth
mpeg2	enable mpeg2 codec for cutscenes
net	enable cloud support via media-libs/sdl2-net
speech	enable text-to-speech support through app-accessibility/speech-dispatcher
unsupported	enable unsupported and/or broken game engines (you're on your own)

solarus

doc	Install doxygen developer documentation.

stratagus

fluidsynth	compile with support for fluidsynth

games-fps

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

doomsday

demo	Install launcher dor doom1.wad from games-fps/doom-data
fluidsynth	Build the FluidSynth sound driver
fmod	Enable support for fmod music and sound effects lib
freedoom	Install launcher for doom1.wad from games-fps/freedoom
tools	Build additional tools such as doomsday-shell, md2tool and texc

duke3d-data

gog	Extract the data from the GOG.com installer.

eduke32

demo	Install the Duke Nukem 3D demo files, provided by games-fps/duke3d-demodata.
fluidsynth	Install media-libs/sdl2-mixer with fluidsynth support.
hrp	Install the Duke Nukem 3D High Resolution Pack.
offensive	Install the Duke Nukem 3D XXX Pack.
opl	Install the Duke Nukem 3D OPL music files.
psx	Install the Duke Nukem 3D PSX high resolution voice files.
sc-55	Install the Duke Nukem 3D Roland SC-55 music files.
sdk	Install the SDK files.
server	Enable support for multiplayer.
tools	Install the support tools for mapster32.
voxels	Install the Duke Nukem 3D Voxels Pack.
vpx	Enable support for media-libs/libvpx.
xmp	Enable support for media-libs/exempi.

gzdoom

fluidsynth	Enable support for MIDI via media-sound/fluidsynth
gtk2	Enable support for GTK+2 instead of GTK+3
mpg123	Enable support for MPEG audio playback via media-sound/mpg123
non-free	Enable non-free components

nexuiz

maps	Install the community map pack

prboom-plus

dumb	Enable support for various tracker-style music formats via media-libs/dumb
fluidsynth	Enable support for MIDI via media-sound/fluidsynth
net	Enable support for network play
portmidi	Enable support for MIDI via media-libs/portmidi
sdl2-image	Enable support for high-resolution texture support via media-libs/sdl2-image
sdl2-mixer	Enable support for MIDI via media-libs/sdl2-mixer

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)

quakeforge

wildmidi	enable libWildMidi support
xdg	enable XDG support

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)

redeclipse

dedicated	Install only as a dedicated game server

rott

demo	Install the shareware version

sauerbraten

server	Compile server support

turtlearena

mumble	Adds player-location (positional audio) support to VoIP
server	Build server target
voice	Adds VoIP support

urbanterror

altgamma	Alternative way for gamma setting with modesetting driver
client	Build binary for client (includes code for non-dedicated server)
mumble	Use Mumble for ingame VoIP (experimental)
server	Build binary for dedicated server
skeetshootmod	Build support for skeetshoot mod for specific maps
voip	Use ioq3 ingame VoIP (experimental)

worldofpadman

maps	Install extra maps (PadPack)

xonotic

ode	Enable support for physics engine from dev-games/ode

yamagi-quake2

client	Build client
ctf	Build support for the 'Capture The Flag' addon
rogue	Build support for the 'Ground Zero' Mission Pack
softrender	Build software renderer
xatrix	Build support for the 'The Reckoning' Mission Pack

games-kids

gcompris

kiosk	Enable kiosk mode by default (for use by small children or on a self-service host machine)

tuxtype

pango	Render fonts using media-libs/sdl-pango instead of media-libs/sdl-ttf

games-misc

little-inferno

bundled-libs	Use bundled libraries.

ponysay

fish-completion	Enable fish completion support
non-free	Install non-free ponies (i.e. from the MLP franchise)

xcowsay

fortune	Enable support for fortune cookies via games-misc/fortune-mod

games-mud

tf

atcp	enable ATCP support.
gmcp	enable GMCP support.
option102	enable telnet option 102 support.

games-puzzle

cuyo

music	Enable playing of background music

nightsky

bundled-libs	Use the upstream provided bundled libraries.

numptyphysics

user-levels	Install some fun user-created levels

pingus

music	Enable playing of background music

sgt-puzzles

gtk3	Use x11-libs/gtk+:3 instead of x11-libs/gtk+:2

tiny-and-big

bundled-libs	Use the upstream provided bundled libraries.

world-of-goo-gog

bundled-libs	Use bundled libs

world-of-goo-hb

bundled-libs	Use bundled libs

xlogical

alt_gfx	Use alternate graphics which are closer to the original Amiga version

games-roguelike

FTL

bundled-libs	Use bundled libraries.

angband

sdl2	Use libsdl2 instead of libsdl
sound	Enable and install sounds

stone-soup

ncurses	Enable for console (uses ncurses) based build. (can be enabled on top of tiles)
tiles	Enable for graphical (tiled) build. (can be enabled on top of ncurses)

tomenet

server	Compile server support

games-rpg

daimonin-client

music	Install extra music

drascula

sound	Install optional audio files

dreamweb

doc	High-resolution scans of the written material in the original UK game box

dungeon-defenders

bundled-libs	Use the upstream provided bundled libraries.

freedroidrpg

devtools	Compile the additional dev tools
profile	Enable the integration of the ingame real-time profiler
sanitize	Compile with address sanitizer

hatoful-boyfriend

gui	Install the GUI for configuring screen resolution and input

hatoful-boyfriend-holiday-star

gui	Install the GUI for configuring screen resolution and input

kqlives

cheats	Enable cheating mode

manaplus

mumble	Enable support for voice chat
pugixml	Use dev-libs/pugixml for XML parsing isntead of dev-libs/libxml2
sdl2	Use libsdl2 instead of libsdl

sumwars

tools	Builds editor tools

to-the-moon

bundled-libs	Use bundled libraries

games-simulation

corsix-th

midi	Adds support for background MIDI music via SDL_mixer

flightgear

dbus	Enable screensaver DBus interaction
gdal	Enable alternative terrain engine based on pagedLOD using sci-libs/gdal
qt5	Build Qt5 launcher application
udev	Enable event-based Input devices through virtual/udev
utils	Build various utilities (fgpanel, fgviewer among others)

openrct2

lightfx	Enables LightFX for better lightning effects.
twitch	Enables streaming of ingame content to Twitch.

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.

train-valley

gui	Install the GUI for configuring screen resolution and input

games-sports

speed-dreams

xrandr	Enable support for the X xrandr extension

xmoto

double-precision	more precise calculations at the expense of speed
editor	Depend on inkscape, scripts to convert svg to level (svg2lvl)

games-strategy

0ad

editor	Include Atlas scenario editor projects
lobby	Enable the use of net-libs/gloox and the multiplayer lobby
nvtt	Support for some uncompressed data formats via media-gfx/nvidia-texture-tools (might be needed for some mods)

colobot

devbuild	TODO
tools	Build tools

colobot-data

music	Enable music support

defcon-demo

system-libs	Use system libraries instead of the ones included in the upstream distribution.

freeciv

aimodules	Support for dynamically loadable AI modules (server-side)
auth	Add authentication capability via mysql, postgres or sqlite3
mapimg	Additional mag image toolkit via media-gfx/imagemagick
modpack	Build the freeciv-modpack-program to download/install mods
server	Enable server support. Disabling this will also make it impossible to start local games.
sound	Add support for sound provided by media-libs/sdl-mixer
system-lua	Use dev-lang/lua instead of the bundled liblua

freesynd

devtools	Build development tools

hedgewars

server	Enable local server

ja2-stracciatella

editor	Adds necessary file to run the editor
ru-gold	Support for russian gold ja2 version

megaglest

editor	Build map editor
fribidi	Enable FriBIDi support
model-viewer	Build model viewer
streflop	Use the library streflop. Out of synchs may occur if not enabled.
tools	Build model import/export tools
unicode	Use unicode strings for wxwidgets
wxuniversal	Use the wxUniversal port which implements the various GUI controls by drawing them itself

naev

mixer	Enables media-libs/sdl-mixer sound backend in addition to media-libs/openal one.

satellite-reign

gui	Install the GUI for configuring screen resolution and input

ufoai

client	Build the main game client
server	Build the dedicated server

uqm

music	download and install music files (large)
remix	download and install music remix files (large)
voice	download and install voice files (large)

wesnoth

fribidi	Support for right-to-left languages
server	Enable compilation of server

games-util

deutex

man	Build and install man pages

gslist

web	Enable the web interface

lgogdownloader

gui	Enable GUI login support for passing reCAPTCHA

wit

fuse	Enable image mount support via fuse

gnome-base

gconf

ldap	Build backend which enables default mail accounts, addressbooks and calendars for Evolution to be configured using each user's LDAP entry."

gdm

bluetooth-sound	Allow loading of bluetooth sound modules. This may be necessary for accessibility screen readers, but may cause bluetooth sound issues for users logging in.
elogind	Use sys-auth/elogind for session management
fprint	Enables experimental fingerprint authentication using sys-auth/fprintd
plymouth	Enable support for smooth transition from sys-boot/plymouth

gnome

classic	Install gnome-extra/gnome-shell-extensions for the Gnome Shell Classic mode
extras	Install additional GNOME applications

gnome-applets

tracker	Build the tracker search bar applet

gnome-control-center

flickr	Add support for using photos from flickr as desktop background
gnome-online-accounts	Enable configuration panel for net-libs/gnome-online-accounts accounts
ibus	Enable support for enhanced input methods through app-i18n/ibus

gnome-extra-apps

games	Install Gnome Games
share	Install the gnome-extra/gnome-user-share personal file sharing tool
shotwell	Install the media-gfx/shotwell photo manager
tracker	Install the app-misc/tracker indexer and the GNOME packages that require it

gnome-keyring

ssh-agent	Use GNOME Keyring to unlock SSH keys. Recommended unless you are using ECDSA or Ed25519 keys.

gnome-light

gnome-shell	Install gnome-base/gnome-shell and x11-wm/mutter for the standard GNOME 3 desktop mode

gnome-session

consolekit	Support sys-auth/consolekit for session tracking
elogind	Support sys-auth/elogind for session tracking

gnome-settings-daemon

elogind	Rely on sys-auth/elogind as runtime logind provider
modemmanager	Enable WWAN support via net-misc/modemmanager
systemd	Rely on sys-apps/systemd as runtime logind provider

gnome-shell

browser-extension	Ensure the presence of extensions.gnome.org native connector gnome-extra/chrome-gnome-shell
elogind	Use sys-auth/elogind for session tracking and suspend support.
ibus	Enable support for enhanced input methods through app-i18n/ibus
telepathy	Ensure presence of telepathy chat integration

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
elogind	Use sys-auth/elogind for session tracking.
fuse	Enables fuse mount points in $HOME/.gvfs for legacy application access
gnome-online-accounts	Enable configuration panel for net-libs/gnome-online-accounts accounts
google	Enables support for accessing Google accounts via dev-libs/libgdata
http	Enable the HTTP/DAV backend using net-libs/libsoup
nfs	Enable NFS client support via net-fs/libnfs.
udev	Enable udev base replacement code for cdda feature

libglade

tools	Install libglade-convert Python script.

libgnomecanvas

glade	Enable glade support

librsvg

tools	Build svg viewer tool

nautilus

gstreamer	Enable the Audio/Video file properties page
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

orbit

pic	Force libname-server-2 to be built as PIC; needed on hardened systems

gnome-extra

cinnamon-control-center

modemmanager	Enable support for mobile broadband devices using net-misc/modemmanager

cinnamon-session

elogind	Rely on sys-auth/elogind as runtime logind provider

eiciel

nautilus	Build gnome-base/nautilus extension

evolution-data-server

berkdb	sys-libs/db support needed to migrate old (pre-3.13 evolution versions) addressbook data
gnome-online-accounts	Enable net-libs/gnome-online-accounts based Google authentication support
oauth	Enable internal OAuth2 authentication support for Google and Outlook.com. If gnome-online-accounts is enabled and used, this is not necessary, but both can be supported at the same time with different setup at runtime
weather	Enable optional weather calendar support

gnome-color-manager

packagekit	Enable support for the distro-neutral package manager GUI PackageKit

gnome-commander

chm	Enable metadata support for Microsoft Compiled HTML Help files
gsf	Add metadata support for OLE, OLE2 and ODF
pdf	Add metadata support for PDF
taglib	Add metadata support for ID3, Vorbis, FLAC and APE
unique	Enable single instance support using dev-libs/libunique

gnome-contacts

telepathy	Start chat from contact details

gnome-shell-extension-gsconnect

nautilus	Install Nautilus extension for sending files via GSConnect

gnome-software

firmware	Enable firmware update support through sys-apps/fwupd
packagekit	Enable module for package manager integration

gnome-system-monitor

systemd	Display sys-apps/systemd metadata, e.g. unit names, for running processes

libgda

canvas	Enable support for x11-libs/goocanvas
http	Enable embedded net-libs/libsoup based server
json	Enable support for JSON format
mdb	Enable support for Microsoft Access database using app-office/mdbtools
reports	Install tools for generating graphical reports
sourceview	Enable support for x11-libs/gtksourceview

libgsf

gtk	Enable use of gdk in thumbnailer

nemo

packagekit	Use packagekit to search for programs to open unknown file types
tracker	Add support for app-misc/tracker search

nm-applet

gcr	Enable advanced certificate chooser, requires app-crypt/gcr
lto	Enable link time optimization
modemmanager	Enable support for mobile broadband devices using net-misc/modemmanager
teamd	Enable teamd configuration editor
wwan	Enable WWAN support

sushi

office	Support viewing file formats such as generated by app-office/libreoffice

synapse

plugins	Build support for plugins using net-libs/rest

gnustep-apps

gemas

projectcenter	Build and install plugin for gnustep-apps/projectcenter

gworkspace

gwmetadata	Enable the metadata indexing and searching system

sogo

activesync	Build the ActiveSync support code

gnustep-base

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-gui

speech	Audio support using app-accessibility/flite

gnustep-make

libobjc2	Enables use of the GNUstep Objective-C runtime (gnustep-base/libobjc2) with non-fragile ABI and sys-devel/clang compiler
native-exceptions	Enables use of the native Objective-C exception support (@try/@catch/@finally) built-in objective-c exceptions with compilers that support it

libobjc2

boehm-gc	Enable Hans Boehm's garbage collector (dev-libs/boehm-gc). Not recommended by upstream

gui-apps

grim

jpeg	Enable JPEG support.
man	Generate and install man pages.

kanshi

man	build and install man pages

mako

icons	Enable support for icons

slurp

man	Generate and install man pages.

swaybg

man	Build and install man pages

swayidle

elogind	Enable support for rootless session via elogind
fish-completion	Enable fish completion support
man	Build and install man pages

swaylock

fish-completion	Enable fish completion support
gdk-pixbuf	Enable additional image format support via the x11-libs/gdk-pixbuf library
man	Build and install man pages

waybar

mpd	Enable support for the Music Player Daemon
network	Enable libnl support for network related features
tray	Enable support for tray

wf-recorder

man	Build and install man pages
opencl	Enable OpenCL

gui-libs

libhandy

glade	Install module and catalog for dev-util/glade

wlroots

X	Enable support for X11 applications (XWayland)
elogind	Enable support for rootless session via elogind
icccm	Use xcb-icccm (from x11-libs/xcb-util-wm) util library for improved Xwayland introspection
x11-backend	Enable support for handling input/output devices through x11-libs/libxcb

gui-wm

sway

X	Enable support for X11 applications (XWayland)
elogind	Enable support for rootless session via elogind
fish-completion	Enable fish completion support
man	Build and install man pages
swaybar	Install 'swaybar': sway's status bar component
swaybg	Install 'swaybg': allows to set a desktop background image
swayidle	Install 'swayidle': idle manager to run commands when user is inactive
swaylock	Install 'swaylock': sway's screen locker
swaymsg	Install 'swaymsg': tool for communicating with a running sway instance
swaynag	Install 'swaynag': shows a message with buttons
tray	Enable support for StatusNotifierItem tray specification
wallpapers	Install sway's default wallpaper image

wayfire

debug	add debugging symbols for error reporting. DISABLE ALL SYSTEM USE FLAGS BEFORE REPORTING BUGS.
gles2	use libglvnd to do animations more efficiently
system-wfconfig	use the system-wide wf-config, else build it as a submodule. DO NOT DISABLE UNLESS YOU KNOW WHAT YOU ARE DOING.
system-wlroots	use the system wide wlroots, else build it as a submodule. DO NOT DISABLE UNLESS YOU KNOW WHAT YOU ARE DOING.

kde-apps

akonadi

designer	Install plugin for dev-qt/designer
kaccounts	Enable support for system-wide defined KAccounts
tools	Install tools for developers and testing

analitza

eigen	Enable dev-cpp/eigen mathematical templates support

ark

zip	Enable ZIP archive support via dev-libs/libzip

artikulate

qtmedia	Enable playback via Qt5Multimedia

cantor

R	Enable dev-lang/R backend support
analitza	Enable kde-apps/analitza backend support
julia	Enable dev-lang/julia backend support
qalculate	Enable sci-libs/libqalculate backend support

dolphin

activities	Track which folders are frequently accessed on a Plasma desktop

gwenview

activities	Enable kactivities support
fits	Enable support for NASA's sci-libs/cfitsio library
kipi	Enable support for the KDE Image Plugin Interface
mpris	Enable support for MPRIS2 interface, requiring dev-qt/qtdbus as dependency.
share	Enable support for a share menu using kde-frameworks/purpose

kalzium

editor	Enable the embedded molecule editor/viewer
solver	Enable the equation solver

kanagram

speech	Enable text-to-speech support

kate

activities	Enable Plasma Activities support via kde-frameworks/kactivities
filebrowser	Enable File System browser tool view
lspclient	Enable LSP (Language Server Protocol) client plugin
plasma	Enable Session Applet addon for KDE Plasma
projects	Enable Project plugin for executing queries on SQL DBs
snippets	Enable Snippets Tool View plugin to manage or download code snippets
sql	Enable SQL plugin for executing queries on SQL DBs

kde-apps-meta

pim	Pull in KDE PIM suite
sdk	Pull in developer-specific meta-packages

kdeadmin-meta

cron	Installs KDE application for virtual/cron configuration

kdecore-meta

share	Install kde-frameworks/purpose for share file context menu actions in kde-apps/dolphin
thumbnail	Install kde-apps/ffmpegthumbs and kde-apps/thumbnailers for thumbnail generation in kde-apps/dolphin
webengine	Enable www-client/falkon which depends on dev-qt/qtwebengine

kdeedu-meta

webengine	Enable kde-apps/kalzium and kde-apps/parley, requiring dev-qt/qtwebengine

kdegraphics-mobipocket

thumbnail	Enables thumbnail generation

kdemultimedia-meta

cdrom	Include packages for optical discs

kdenetwork-meta

dropbox	Enable support for Dropbox in kde-apps/dolphin via kde-apps/dolphin-plugins-dropbox
telepathy	Enable support for Plasma Telepathy (instant messaging) integration via kde-apps/plasma-telepathy-meta

kdenlive

freesound	Enable freesound.org credentials support via dev-qt/qtwebkit to download files
share	Enable support for a share menu using kde-frameworks/purpose

kdepim-addons

importwizard	Enable additional import plugins for kde-apps/akonadi-import-wizard
markdown	Enable Markdown support via app-text/discount

kdepim-meta

bogofilter	Install mail-filter/bogofilter for spam filter support in kde-apps/kmail
clamav	Install app-antivirus/clamav for virus detection support in kde-apps/kmail
spamassassin	Install mail-filter/spamassassin for spam filter support in kde-apps/kmail

kdesdk-meta

git	Enable support for Git VCS in kde-apps/dolphin via kde-apps/dolphin-plugins-git
mercurial	Enable support for Mercurial VCS in kde-apps/dolphin via kde-apps/dolphin-plugins-mercurial
subversion	Enable support for Apache Subversion VCS in kde-apps/dolphin via kde-apps/dolphin-plugins-subversion

kdeutils-meta

7zip	Install app-arch/p7zip for 7zip archive support in kde-apps/ark
floppy	Install kde-apps/kfloppy to format and create DOS or ext2fs filesystems in a floppy.
gpg	Install kde-apps/kgpg which depends on kde-apps/akonadi
lrz	Install app-arch/lrzip for LRZ archive support in kde-apps/ark
rar	Install one of app-arch/rar, app-arch/unrar or app-arch/unar for RAR archive support in kde-apps/ark
webengine	Enable kde-apps/kimagemapeditor, requiring dev-qt/qtwebengine

keditbookmarks

man	Build and install man pages

kget

bittorrent	Enable bittorrent transfer plugin through net-libs/libktorrent
gpg	Enable signature verification by GpgME++ via app-crypt/gpgme
mms	Enable MMS (Microsoft Media Server) plugin through media-libs/libmms

kig

geogebra	Support files created by sci-mathematics/geogebra
scripting	Support Python scripting

kio-extras

activities	Enable activities kioslave and fileitem plugin
man	Enable manpages kioslave
nfs	Enable NFS support using net-libs/libtirpc
phonon	Enable file audio preview plugin using media-libs/phonon
sftp	Enable SFTP protocol support using net-libs/libssh
taglib	Enable audio thumbnails via media-libs/taglib

kipi-plugins

flashexport	Build the flash export plugin
mediawiki	Build the mediawiki export plugin
remotestorage	Build plugin for remote storage using network protocols such as FTP, SSH, SAMBA via kde-frameworks/kio
vkontakte	Build plugin for vkontakte.ru

kitinerary

barcode	Enable support for PDF417 and Aztec barcode decoding using media-libs/zxing-cpp

kmag

keyboardfocus	Enable keyboard focus tracking

knights

speech	Enable text-to-speech support

konqueror

activities	Enable kactivities support
speech	Build text-to-speech plugin

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.
nowlistening	Shows song you currently listen to in your status/etc. Bindings for many players.
oscar	Enable Oscar (AIM/ICQ) IM protocol support
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
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 ;])
zeroconf	Enable Link-Local Messaging via the bonjour protocol.

kpimtextedit

designer	Build plugins for dev-qt/designer

ktp-accounts-kcm

experimental	Enables disabled telepathy services (currently only steam)

ktp-common-internals

otr	Enable support for encrypted conversations using Off-The-Records messaging
sso	Enable support for Single sign-on through KAccounts

ktp-text-ui

speech	Enable incoming messages to be read out using text-to-speech

kwave

qtmedia	Enable playback via Qt5Multimedia

kwrite

activities	Enable Plasma Activities support via kde-frameworks/kactivities

libkdepim

designer	Build plugins for dev-qt/designer

libkleo

fancyviewer	Use kde-apps/kpimtextedit for an improved audit log viewer

libksane

kwallet	Enable encrypted storage of passwords with kde-frameworks/kwallet

mailcommon

designer	Build plugins for dev-qt/designer

marble

aprs	Enable support for APRS data sources
designer	Install plugin for dev-qt/designer
geolocation	Enable position information via dev-qt/qtpositioning
phonon	Enable sound support via media-libs/phonon
shapefile	Enable support for ESRI shapefiles
webengine	Use dev-qt/qtwebengine for embedded web browser

okular

chm	Enable support for Microsoft Compiled HTML Help files
epub	Enable E-Book support via app-text/ebook-tools
image-backend	Enable image viewing support
markdown	Enable Markdown support via app-text/discount
mobi	Enable mobipocket support
mobile	Enable Plasma mobile support
plucker	Enable Plucker E-Book for Palm OS devices support
share	Enable support for a share menu using kde-frameworks/purpose
speech	Enable text-to-speech support

pimcommon

designer	Build plugins for dev-qt/designer

spectacle

kipi	Enable support for the KDE Image Plugin Interface
share	Enable support for a share menu using kde-frameworks/purpose

step

qalculate	Enable the libqalculate library for unit conversion

umbrello

php	Enable PHP import support using dev-util/kdevelop and dev-util/kdevelop-pg-qt

yakuake

absolute-position	Use kde-frameworks/kwayland for absolute window positioning in KWin

kde-frameworks

frameworkintegration

appstream	Enable AppStream software metadata support

kcompletion

designer	Build plugins for dev-qt/designer

kconfigwidgets

designer	Build plugins for dev-qt/designer
man	Build and install man pages

kded

man	Build and install man pages

kdewebkit

designer	Build plugins for dev-qt/designer

kfilemetadata

epub	Enable support for reading EPUB ebook metadata
office	Enable support for reading ODF and OOXML metadata

kiconthemes

designer	Build plugins for dev-qt/designer

kimageformats

eps	Support the EPS graphics file format

kinit

caps	Capabilities support for improved security and better OOM handling
man	Build and install man pages

kio

designer	Build plugins for dev-qt/designer
kwallet	Enable permanent storage of passwords for kpasswdserver with kde-frameworks/kwallet

kitemmodels

qml	Enable QML support via dev-qt/qtdeclarative

kitemviews

designer	Build plugins for dev-qt/designer

knotifications

phonon	Play notification sounds via media-libs/phonon instead of media-libs/libcanberra
speech	Enable text-to-speech notification support

knotifyconfig

phonon	Add sound support via media-libs/phonon

kpackage

man	Build and install man pages

kplotting

designer	Build plugins for dev-qt/designer

kservice

man	Build and install man pages

ktexteditor

editorconfig	Enable support for EditorConfig configuration files

ktextwidgets

designer	Build plugins for dev-qt/designer
speech	Enable text-to-speech support

kwallet

gpg	Support wallets with GnuPG encryption in addition to the default blowfish-encrypted file
man	Build and install man pages

kwidgetsaddons

designer	Build plugins for dev-qt/designer

kxmlgui

designer	Build plugins for dev-qt/designer

networkmanager-qt

teamd	Enable Teamd control support

prison

qml	Enable QML/QtQuick support via dev-qt/qtdeclarative

purpose

dolphin	Enable support for sharing files from kde-apps/dolphin
kaccounts	Enable support for system-wide defined KAccounts

sonnet

aspell	Enable the app-text/aspell spell-checking backend
designer	Build plugins for dev-qt/designer
hunspell	Enable the app-text/hunspell spell-checking backend

kde-misc

kdeconnect

X	Enable remote input mousepad plugin using x11-libs/libfakekey
pulseaudio	Enable system volume control plugin using media-sound/pulseaudio
wayland	Enable remote input mousepad plugin using kde-frameworks/kwayland

kimtoy

scim	Enable Smart Common Input Method support

kio-gdrive

kaccounts	Use kde-apps/kaccounts-integration backend (default) instead of dev-libs/qtkeychain

kmarkdownwebview

webkit	Use dev-qt/qtwebkit instead of dev-qt/qtwebengine

tellico

discid	Add support for reading disc IDs from audio CDs
yaz	Add support for searching Z39.50 databases

kde-plasma

discover

firmware	Enable support for firmware upgrades using sys-apps/fwupd

kde-cli-tools

kdesu	Build graphical frontend for kde-frameworks/kdesu

kdeplasma-addons

share	Enable applet for quickly sharing data to a variety of sources
webengine	Enable dictionary and web browser applets using dev-qt/qtwebengine

kinfocenter

pci	Show advanced PCI information

kscreenlocker

consolekit	Support for killing the screenlocker when sys-auth/consolekit is the session tracker

ksysguard

pcap	Enable per-process network statistic collection using net-libs/libpcap

kwin

multimedia	Enable effect video button in desktop effects KCM

libksysguard

webengine	Enable display of detailed memory information using dev-qt/qtwebengine.

plasma-desktop

ibus	Use ibus input method via app-i18n/ibus
scim	Enable applets that use app-i18n/scim

plasma-meta

browser-integration	Enable integration with Chrome/Firefox with browser extensions
crypt	Pull in kde-plasma/plasma-vault for encrypted vaults integration
desktop-portal	Enable sys-apps/xdg-desktop-portal backend implementation for Plasma
discover	Pull in resources management GUI; a centralised GHNS alternative and optional sys-apps/fwupd frontend
display-manager	Pull in a graphical display manager
elogind	Use sys-auth/elogind for session tracking
grub	Pull in Breeze theme for sys-boot/grub
gtk	Enable Breeze widget style and system settings module for GTK+
kwallet	Enable support for KWallet auto-unlocking via kde-plasma/kwallet-pam
legacy-systray	Add support for legacy applications using kde-plasma/xembed-sni-proxy
plymouth	Pull in Breeze theme for sys-boot/plymouth
pulseaudio	Install Plasma applet for PulseAudio volume management
qrcode	Enable support for easy WiFi network sharing using QR codes with kde-plasma/plasma-nm
sddm	Pull in the x11-misc/sddm display manager and system settings module
sdk	Pull in kde-plasma/plasma-sdk for Plasma development
thunderbolt	Pull in kde-plasma/plasma-thunderbolt control center module
wallpapers	Install wallpapers for the Plasma Workspace

plasma-nm

modemmanager	Enable support for mobile broadband devices
openconnect	Build support for the OpenConnect VPN client
teamd	Enable Teamd control support

plasma-workspace

appstream	Enable AppStream software metadata support
geolocation	Enables dataengine providing location information
qalculate	Enable Qalculate runner using sci-libs/libqalculate
qrcode	Enable support for creating QR codes from clipboard data using kde-frameworks/prison
telemetry	Enable User Feedback control module for kde-plasma/systemsettings

powerdevil

brightness-control	Enable screen brightness control using app-misc/ddcutil
wireless	Enable wireless energy saving actions via kde-frameworks/bluez-qt and kde-frameworks/networkmanager-qt

xdg-desktop-portal-kde

screencast	Enable screencast portal using media-video/pipewire

lxde-base

lxdm

consolekit	Enables support for authorization using consolekit
gtk3	Use GTK+3 instead of 2

lxterminal

gtk3	Use GTK+3 instead of GTK+2

lxqt-base

liblxqt

backlight	Enable backlight control features.

lxqt-config

monitor	Build monitor settings tool
touchpad	Build touchpad settings tool

lxqt-meta

about	Install lxqt-base/lxqt-about
admin	Install lxqt-base/lxqt-admin
archiver	Install app-arch/lxqt-archiver
display-manager	Install a graphical display manager
filemanager	Install x11-misc/pcmanfm-qtfile manager
lightdm	Install x11-misc/lightdmdisplay manager
lximage	Install media-gfx/lximage-qtimage viewer
minimal	Do not install x11-wm/openboxwindow manager
nls	Install dev-qt/qttranslations to better support different locales
powermanagement	Install lxqt-base/lxqt-powermanagement package
processviewer	Install x11-misc/qps package
screenshot	Install x11-misc/screengrab package
sddm	Install x11-misc/sddm display manager
ssh-askpass	Install lxqt-base/lxqt-openssh-askpass user password prompt tool
sudo	Install lxqt-base/lxqt-sudo
terminal	Install x11-terms/qterminal package
trash	Install gnome-base/gvfs to enable 'trash' functionality in x11-misc/pcmanfm-qt

lxqt-panel

colorpicker	Build colorpicker plugin
cpuload	Build cpuload plugin
desktopswitch	Build desktopswitch plugin
directorymenu	Build directorymenu plugin
dom	Build dom plugin
kbindicator	Build kbindicator plugin
mainmenu	Build mainmenu plugin
mount	Build mount plugin
networkmonitor	Build networkmonitor plugin
quicklaunch	Build quicklaunch plugin
sensors	Build sensors plugin
showdesktop	Build showdesktop plugin
spacer	Build spacer plugin
statusnotifier	Build statusnotifier plugin
sysstat	Build sysstat plugin
taskbar	Build taskbar plugin
tray	Build tray plugin
volume	Build volume plugin
worldclock	Build worldclock plugin

lxqt-session

themes	Install LXQt themes and graphics

mail-client

aerc

notmuch	Enable support for net-mail/notmuch

alot

doc	Install user manual and API documentation

alpine

chappa	enhance Alpine by applying Eduardo Chappa's patches
onlyalpine	installs only the alpine binary, so it does not collied with pico and/or pine
passfile	Adds support for caching passwords into a file between sessions
smime	Enable support for S/MIME

balsa

crypt	Adds support for GnuPG encryption
rubrica	Adds support for rubrica addressbook

claws-mail

archive	Enable archiving plugin
bogofilter	Build mail-filter/bogofilter plugin
dillo	Enable dillo html viewer plugin
gdata	Enable plugin for access to Google data providers
gtk3	Build support for GTK+3
libcanberra	Enable sound notification in connection with USE=notification
libindicate	Enable notification through DBUS in connection with USE=notification
libnotify	Enable notification on the desktop in connection with USE=notification
litehtml	Enable dev-libs/gumbo html viewer plugin
notification	Notification for new mail in different way, see also USE flags libcanberra, libindicate and libnotify
pgp	Enable PGP support
sieve	Build plugin for sieve filter support
smime	Build plugin for S/MIME support
spam-report	Enable plugin for spam reporting to various services
spamassassin	Build mail-filter/spamassassin plugin
valgrind	Add support for memory debugging using valgrind

evolution

archive	Enable archives support in attachments via app-arch/gnome-autoar
bogofilter	Build mail-filter/bogofilter plugin
geolocation	Enable support for displaying contacts on a map inside evolution using media-libs/libchamplain
highlight	Enable text highlighting plugin
ldap	Enable support for fetching contacts from an LDAP or Active Directory server using net-nds/openldap
spamassassin	Build mail-filter/spamassassin plugin
weather	Enable optional weather calendar support
ytnef	Enable optional TNEF attachments parser support using net-mail/ytnef

geary

ytnef	Enable optional TNEF attachments parser support using net-mail/ytnef

mutt

autocrypt	Enable autocrypt.org support
berkdb	Enable sys-libs/db database backend for header caching
gdbm	Enable sys-libs/gdbm database backend for header caching
gpgme	Build gpgme backend to support S/MIME, PGP/MIME and traditional/inline PGP
hcache	Enable header cache, one database backend needs to be enabled
lmdb	Enable dev-db/lmdb database backend for header caching
pgp-classic	Build classic_pgp backend to support PGP/MIME and traditional/inline PGP
pop	Enable support for POP3 mailboxes
smime-classic	Build classic_smime backend to support S/MIME
smtp	Enable support for direct SMTP delivery
tokyocabinet	Enable dev-db/tokyocabinet database backend for header caching

neomutt

berkdb	Enable BDB (Berkley DB) backend for header caching
gdbm	Enable GDBM (GNU dbm) backend for header caching
gpgme	Build gpgme backend to support S/MIME, PGP/MIME and traditional/inline PGP
kyotocabinet	Enable Kyoto Cabinet database backend for header caching
lmdb	Enable LMDB (Lightning Memory-Mapped Database) backend for header caching
notmuch	Enable support for net-mail/notmuch
pgp-classic	Build classic_pgp backend to support PGP/MIME and traditional/inline PGP
pgp_classic	Build classic_pgp backend to support PGP/MIME and traditional/inline PGP
qdbm	Enable QDBM (Quicker Database Manager) database backend for header caching
smime-classic	Build classic_smime backend to support S/MIME
smime_classic	Build classic_smime backend to support S/MIME
tokyocabinet	Enable Tokyo Cabinet database backend for header caching

roundcube

change-password	Allow users to change passwords through Roundcube
enigma	Add dependencies to support server-side GnuPG signing and/or encryption through the enigma plugin
ldap	Add dependencies to support connecting to an LDAP address book server
managesieve	Add dependencies to support the sieverules plugin

s-nail

kerberos	If network is enabled, this adds support for GSSAPI login on IMAP through virtual/krb5.
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.

sylpheed

oniguruma	Use dev-libs/oniguruma for regular expression

thunderbird

bindist	Disable official Firefox/Thunderbird branding (icons, name) which are not binary-redistributable according to upstream.
clang	Use Clang compiler instead of GCC
custom-optimization	Build with user-specified compiler optimizations (-Os, -O0, -O1, -O2, -O3) from CFLAGS (unsupported)
eme-free	Disable EME (DRM plugin) cabability at build time
gmp-autoupdate	Allow Gecko Media Plugins (binary blobs) to be automatically downloaded and kept up-to-date in user profiles
gtk2	Use the cairo-gtk2 rendering engine instead of the default cairo-gtk3
lightning	Enable app-global calendar support (note 38.0 and above bundles calendar support when this flag is off)
lto	Enable Link Time Optimization (LTO). Requires Gold linker when using GCC or LDD linker when using Clang
mozdom	Enable Mozilla's DOM inspector
pgo	Add support for profile-guided optimization using gcc-4.5, for faster binaries. This option will double the compile time.
rust	Enable support for using rust compiler (experimental)
system-av1	Use the system-wide media-libs/dav1d and media-libs/libaom library instead of bundled.
system-cairo	Use the system-wide x11-libs/cairo instead of bundled.
system-harfbuzz	Use the system-wide media-libs/harfbuzz and media-gfx/graphite2 instead of bundled.
system-icu	Use the system-wide dev-libs/icu instead of bundled.
system-jpeg	Use the system-wide media-libs/libjpeg-turbo instead of bundled.
system-libevent	Use the system-wide dev-libs/libevent instead of bundled.
system-libvpx	Use the system-wide media-libs/libvpx instead of bundled.
system-sqlite	Use the system-wide dev-db/sqlite installation with secure-delete enabled
system-webp	Use the system-wide media-libs/libwebp instead of bundled.

thunderbird-bin

crashreporter	Enable crash reporter for bugs

trojita

password	Store passwords securely via dev-libs/qtkeychain
pim	Enable support for KDE PIM resources integration via kde-apps/akonadi addressbook plugin

mail-filter

MailScanner

exim	Set mail-mta/exim to used MTA
postfix	Set mail-mta/postfix to used MTA
spamassassin	Enable usage of mail-filter/spamassassin for spam protection

amavisd-new

courier	Add courier support
dkim	Add DomainKeys Identified Mail support
qmail	Add qmail support
razor	Add support for mail-filter/razor
rspamd	Add support for mail-filter/rspamd extension (HTTP only)
rspamd-https	Add support for mail-filter/rspamd extension (both HTTP and HTTPS)
spamassassin	Add support for mail-filter/spamassassin
zmq	Add support for zeromq sockets

bogofilter

tokyocabinet	Enable Tokyo Cabinet database support

dcc

rrdtool	Enable net-analyzer/rrdtool interface scripts

dspam

daemon	Enable support for DSPAM to run in --daemon mode
debug	Enable debugging support (don't enable this unless something needs testing!)
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-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	Build with user homedir support
virtual-users	Build with virtual-users support

libmilter

poll	Use poll instead of select

maildrop

authlib	Add courier-authlib support
dovecot	Add dovecot authentication support
tools	Install maildirmake and deliverquota tools
trashquota	Count deleted messages as part of the maildir quota

mimedefang

poll	Use poll instead of select

opendkim

ldap	Enable openldap as a dataset facilitator or keys, determining domains to sign for, and any other dataset that opendkim supports.
lmdb	Add support for using dev-db/lmdb
lua	Enables control over signature verification, filtering and policy to be controlled by user defined lua scripts.
memcached	Add support for using dev-libs/libmemcached
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.
querycache	Add support for query caching (requires 'berkdb' flag)
sasl	Used to authenticate to a LDAP server in various ways if required.
stats	Add support for statistics (requires 'opendbx' flag)
unbound	Use the unbound dnssec library to perform DKIM DNS queries.

opendmarc

reports	Install the reports binaries: expire, import, reports, params
spf	Use the mail-filter/libspf2 for Sender Policy Framework checking

postfwd

tools	Install additional tools for testing postfwd

postgrey

targrey	Enables the targrey patch

pyzor

gdbm	Enables the Gdbm back-end database engine for pyzord
gevent	Use dev-python/gevent to enable asynchronous operation
pyzord	Enable the pyzord server daemon
redis	Enables the redis back-end database engine for pyzord through dev-python/redis-py

rmilter

dkim	Enable support for DomainKeys Identified Mail
memcached	Enable support for memcached

rspamd

pcre2	Use dev-libs/libpcre2

spamassassin

cron	Install a cron job to update SpamAssassin's rules daily.
qmail	Build qmail functionality and docs

spamdyke

ssl	Enables TLS protocol for spamdyke

mail-mta

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

arc	Adds support for Authenticated Receive Chain (ARC)
dane	Adds support for DNS-based Authentication of Named Entities
dcc	Adds support for Distributed Checksum Clearinghouse (DCC)
dkim	Adds support for DomainKeys Identified Mail (DKIM)
dlfunc	Install local_scan.h header to compile separate dlfunc libraries
dmarc	Adds support for DMARC
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
pkcs11	Require pkcs11 support in net-libs/gnutls with USE=gnutls
prdr	Adds support for Per-Recipient Data Response
proxy	Add support for being behind a proxy, such as HAProxy
redis	Adds support for querying dev-db/redis
spf	Adds support for Sender Policy Framework
srs	Adds support for Sender Rewriting Scheme
tpda	Adds support for Transport Post-Delivery Actions

msmtp

daemon	Build/install msmtpd MTA daemon
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
pop3	Include POP3 server

opensmtpd

mta	Enable this to install as system-wide MTA

postfix

dovecot-sasl	Enable net-mail/dovecot protocol version 1 (server only) SASL implementation
eai	Add support for SMTPUTF8
ldap-bind	Add support for binding to LDAP backend using dev-libs/cyrus-sasl
lmdb	Add support for using dev-db/lmdb for lookup tables
memcached	Add support for using net-misc/memcached for lookup tables

qpsmtpd

postfix	create user with permissions for proper postfix interaction

ssmtp

mta	Install symlinks for sendmail-compatible MTA.

mate-base

caja

mate	Install x11-themes/mate-icon-theme which is needed when this package is used in the MATE desktop environment.
packagekit	Enable support for installing via PackageKit based on mimetype

mate

base	Install base MATE Desktop applications that are recommended for the most common usage; for example, this installs the file manager. Disable this and other USE flags if you want a more minimal MATE Desktop.
extras	Install additional MATE Desktop applications that are recommended for extended usage of the MATE Desktop as upstream sees it; for example, this installs MATE Desktop's office related applications. Disable this if you plan to use your own non-MATE Desktop alternatives or a custom mixture of MATE and non-MATE packages.
help	Install gnome-extra/yelp to handle in application help menus and documentation browsing
notification	Force notification daemon to default to MATE's notification daemon. Enabled by default. Disable if it causes conflicts with other installed desktop environments.
themes	Install MATE Desktop's themes; if you use other themes, you can disable this to spare some space and time.

mate-applets

cpupower	Enable support for cpu frequency manipulation using sys-power/cpupower

mate-applets-meta

appindicator	Pull in mate-extra/mate-indicator-applet for AppIndicator applet
sensors	Pull in mate-extra/mate-sensors-applet for hw sensors applet

mate-control-center

accountsservice	Add support for AccountsService

mate-session-manager

xtrans	Build with Xtrans support; WARNING: Disabling this flag will result in ICE binding on all interfaces

mate-settings-daemon

rfkill	build support for rfkill

mate-extra

caja-extensions

cdr	Add an extension to burn files to cds using app-cdr/brasero.
gajim	Add an extension to support net-im/gajim.
image-converter	Add image conversion support.
mail	Add an extension to support e-mail functionality.
open-terminal	Add an extension to support an open terminal.
pidgin	Add an extension to support net-im/pidgin
share	Add an extension to support sharing files.
wallpaper	Add an extension to support setting an image as the current wallpaper

mate-polkit

accountsservice	Support extraction of data from AccountsService

mate-power-manager

applet	Enable building of the MATE applet.

mate-screensaver

consolekit	Enable support for sys-auth/consolekit

mate-utils

applet	Enable the mate dictionary applet

media-fonts

corefonts

tahoma	Also install the Tahoma font. Due to the lack of a free bold variant, this may render badly. See bug 184790.

culmus

ancient	Install ancient semitic scripts
fancy	Install fancy fonts
fontforge	Use media-gfx/fontforge to build fonts from source
taamey	Install taamey fonts

dejavu

fontforge	Use media-gfx/fontforge to build fonts from source

fontawesome

otf	Install the OpenType version of the font
ttf	Install the TrueType version of the font

ibm-plex

otf	Install OTF fonts
ttf	Install TTF fonts

infinality-ultimate-meta

free	Install fonts for the "free" preset
latin	Install additional latin fonts
minimal	Install a minimal set of fonts
ms	Install (free) fonts for the "ms" preset

intlfonts

bdf	Install BDF fonts in addition to PCF
non-free	Install non-free Tibetan fonts

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

noto

extra	Install full upstream font set

noto-emoji

buildfont	Build Noto Emoji font with supplied images.

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)
center-tilde	Place the '~' character vertically centered on the line instead of to the top.
distinct-l	ll2 variant with more distinctive l (lowercase L)
pcf	Install Portable Compiled Font (PCF) (required for X11)
pcf-unicode-only	Remove non-unicode PCF fonts that could be problematic. See bug #520222.
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)
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)

unifont

fontforge	Use media-gfx/fontforge to build fonts from source
utils	Install unifont utilities

media-gfx

ahoviewer

rar	Rar archive support
zip	Zip archive support

album

plugins	Install optional plugins
themes	Install optional themes

alembic

arnold	Add support for arnold renderer (experimental)
boost	Use dev-libs/boost library
examples	Install alembic examples
hdf5	Add support sci-libs/hdf5
maya	Compile Alembic plugin for Maya (experimental)
prman	Compile Alembic plugin for Renderman (experimental)
python	Build pyalembic python bindings (needs dev-python/pyilmbase)
test	Build and run the test-suite
zlib	Use sys-libs/zlib for compressions

apngasm

7z	Enable support for 7zip compression
zopfli	Enable support for Zopfli compression

asymptote

boehm-gc	Enables using the Boehm-Demers-Weiser conservative garbage collector
offscreen	Enables off-screen rendering
sigsegv	Enables using dev-libs/libsigsegv

blender

bullet	Enable Bullet (Physics Engine).
collada	Add support for Collada interchange format through media-libs/opencollada.
color-management	Enable color management via media-libs/opencolorio.
cuda	Build cycles renderer with nVidia CUDA support.
cycles	Build cycles renderer (requires media-libs/openimageio and dev-libs/boost).
dds	Adds DDS textures support to Blender.
doc	Build C and Python API documentation directly from the source code.
elbeem	Adds surface fluid simulation to Blender using El'Beem library.
game-engine	Adds Game Engine support to Blender.
headless	Build without graphical support (renderfarm, server mode only).
llvm	Enable features depending on llvm.
man	Build and install man pages.
ndof	Enable NDOF input devices (SpaceNavigator and friends).
opencl	Allow OpenCL Graphics Acceleration. This may require extra graphics card drivers.
openimageio	Enable OpenImageIO Support
opensubdiv	Add rendering support form OpenSubdiv from Dreamworks Animation through media-libs/opensubdiv.
openvdb	Add GPU preview rendering. Only works with nVidia cards.
osl	Add support for OpenShadingLanguage scripting.
player	Build the Blender Player. THis requires the Game engine.
test	Build the provided unit tests.
valgrind	Add support for memory debugging using dev-util/valgrind

chafa

tools	Build command-line tools

cura

usb	Access 3D printers via USB

darktable

flickr	Add support for uploading photos to flickr
geolocation	Enable geotagging support
kwallet	Enable encrypted storage of passwords with kde-frameworks/kwallet
opencl	Enable opencl support
pax_kernel	Triggers paxmarking of main darktable binary

digikam

addressbook	Enable akonadi contact integration
dnn	Build neural network faces engine module
heif	Enable support for ISO/IEC 23008-12:2017 HEIF files using media-libs/x265
imagemagick	Enable support for additional image formats such as XCF, FITS, HEIC etc.
lensfun	Enable support for media-libs/lensfun
marble	Enable support for geolocation using kde-apps/marble
mediaplayer	Enable support for media player using media-libs/qtav
panorama	Build the panorama plugin which requires media-gfx/hugin
semantic-desktop	Enable kde-frameworks/kfilemetadata support
vkontakte	Build net-libs/libkvkontakte plugin for vkontakte.ru
webkit	Build with dev-qt/qtwebkit instead of dev-qt/qtwebengine

eog-plugins

map	Enable world map display using media-libs/libchamplain
picasa	Enable uploading to Google's Picasa Web Albums

eom

imagemagick	Use media-gfx/imagemagick as an external backend for the thumbnailer

exact-image

swig	Adds Swig support dev-lang/swig

exiv2

webready	Support reading metadata over the internet

fbida

X	Install the Motif based image viewer "ida"
fbcon	Install the framebuffer image viewer "fbi"
ghostscript	Install the framebuffer ghostscript viewer "fbgs"

fim

bmp	Enable BMP file support
dia	Enable DIA file support via app-office/dia
imagemagick	Use convert from media-gfx/imagemagick as fallback file opener
pcx	Enable PCX file support
xfig	Enable FIG file support via media-gfx/xfig

fontforge

truetype-debugger	Enable truetype debugger in fontforge
woff2	Enable support for WOFF2 format

fotowall

webcam	Enable webcam support

freewrl

glew	Enable glew extensions
java	Build and install java EAI/SAI support library
libeai	Build EAI C library
opencl	Enable OpenCL support
osc	Allows for OSC-based control and communication between multiple freewrl instances
rbp	Enable support for Rigid Body Physics

geeqie

ffmpegthumbnailer	Enable video thumbnail support with media-video/ffmpegthumbnailer
gpu-accel	Enable GPU acceleration support - experimental
gtk3	Link against x11-libs/gtk+:3 instead of x11-libs/gtk+:2
map	Enable items map display - experimental

gimp

heif	Enable support for ISO/IEC 23008-12:2017 HEIF files
smp	Enable support for multiprocessors
vector-icons	Enable support for vector icons (experimental)

gmic

cli	Build CLI interface
krita	Build media-gfx/krita plugin
opencv	Enable support for webcams using the OpenCV library

gnofract4d

doc	Install user manual

gnome-photos

flickr	Ensure runtime Flickr support

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

X	Builds lefty front-end, builds plugin -Txlib, and enables support for x11 in various other modules (needs cairo)
devil	Enables DevIL output plugin -Tdevil
gdk-pixbuf	Enables gdk-pixbuf2 plugin
gtk	Enables gtk+ output plugin -Tgtk (needs cairo)
gts	Enables support for GNU Triangulated Surface Library (required for sfdp to work)
lasi	Enables PostScript output via media-libs/lasi, for plugin -Tlasi (needs cairo)

gthumb

http	Enable webservice integration through net-libs/libsoup
json	Compile code that uses the libjson-glib library
slideshow	Enable slideshow plugin

hugin

sift	automatically align images with media-gfx/autopano-sift-C

imagemagick

corefonts	Use media-fonts/corefonts which is required by some commands
fpx	Enable media-libs/libfpx support
hdri	Enable High Dynamic Range Images formats
heif	Enable support for ISO/IEC 23008-12:2017 HEIF/HEIC image format using media-libs/libheif
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
q8	Set quantum depth value to 8

imv

freeimage	Use media-libs/freeimage as image library
libnsgif	Use media-libs/libnsgif as image library

inkscape

cdr	Enable support for CorelDRAW files via media-libs/libcdr
dia	Enable DIA flow chart import via app-office/dia
inkjar	Enable support for OpenOffice.org SVG jar files
latex	Enable rendering of LaTeX formulas
svg2	Enable support for new SVG2 features
uniconvertor	Enable conversion of vector graphic files via media-gfx/uniconvertor (needs Python 2)
visio	Enable support for Microsoft Visio diagrams via media-libs/libvisio
wpg	Enable support for WordPerfect graphics via app-text/libwpg

iscan-plugin-gt-f500

minimal	Install the firmware only, and not the plugin.

jpeg2ps

metric	Default to A4 paper size

kphotoalbum

kipi	Support for the KDE Image Plugin Interface
map	Enable map display support using kde-apps/libkgeomap
share	Enable support for a share menu using kde-frameworks/purpose

krita

color-management	Enable color management via media-libs/opencolorio
heif	Enable support for ISO/IEC 23008-12:2017 HEIF/HEIC image format using media-libs/libheif
qtmedia	Enable sound support for animations via dev-qt/qtmultimedia
vc	Enable support for dev-libs/vc, could be a significant speed boost

librecad

3d	Require all 2D coordinates stored as 3D
tools	Build additional tool programs: tff2lff

luminance-hdr

fits	Enable support for the FITS format

mandelbulber

opencl	Enable GPU rendering support using OpenCL

nomacs

opencv	Build support for media-libs/opencv

nvidia-texture-tools

cg	Enable NVIDIA C graphics compiler toolkit plug-in
glew	Enable support for The OpenGL Extension Wrangler Library (media-libs/glew)

openclipart

gzip	Compresses clip art using gzip

openexr_viewers

cg	Add support for nvidia's cg shaders

openvdb

abi3-compat	Disables newer features to maintain compatibility with ABI3. Enabled by default.
abi4-compat	Disables newer features to maintain compatibility with ABI4. Enabled by default.

photoqt

devil	Support additional image formats using media-libs/devil
freeimage	Support additional image formats using media-libs/freeimage

pngcrush

system-libs	Use libpng and libz provided by system

potrace

metric	default to a4 paper size and metric measurement

povray

io-restrictions	POV-Ray's mechanism for control of I/O operations
mkl	Enable support for Intel Vector Math Library, part of sci-libs/mkl

pqiv

archive	Enable support for images in archives and cbX comic book files

pstoedit

emf	Enable media-libs/libemf support
pptx	Enable support for generating PowerPoint pptx files

qimgv

video	Add support for gif/webm playback via libmpv

shotwell

opencv	Enable face detection via media-libs/opencv

sigal

s3	Enables support for the Amazon S3 service.

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

xpaint

pgf	Support for loading PGF images

xsane

ocr	Enable support for Optical Character Recognition reader

yafaray

blender	Install addon for media-gfx/blender
fastmath	Enable mathematic approximations to make code faster
fasttrig	Enable trigonometric approximations to make code faster
opencv	Use media-libs/opencv

media-libs

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.
thread-safety	thread-safe API functions

alure

dumb	Enable media-libs/dumb module library support
fluidsynth	Enables Fluidsynth MIDI software synthesis

assimp

samples	Build viewer library
tools	Build assimp tool binary

aubio

double-precision	Compile in double precision mode.

avidemux-core

nvenc	Adds support for NVIDIA Encoder (NVENC) API for hardware accelerated encoding on NVIDIA cards.
system-ffmpeg	Use the ffmpeg provided by the system.

avidemux-plugins

aften	Enable A/52 (AC-3) audio encoder support.
amr	Enable Adaptive Multi-Rate format support via media-libs/opencore-amr.
dcaenc	Enable DTS Coherent Acoustics audio encoder support via media-sound/dcaenc.
fdk	Adds support for encoding AAC using media-libs/fdk-aac.
fribidi	Enable unicode bidirectional algorithm support via dev-libs/fribidi.
nvenc	Adds support for NVIDIA Encoder (NVENC) API for hardware accelerated encoding on NVIDIA cards.
twolame	Enable TwoLAME support via media-sound/twolame, an optimised MPEG Audio Layer 2 (MP2) encoder.
vpx	Enable WebM VP8 Codec SDK support via media-libs/libvpx.
x265	Enables HEVC support with media-libs/x265.

cal3d

16bit-indices	Enables use of 16bit indices

chromaprint

tools	Build and install fpcalc and fpcollect tools

clutter

egl	Enable EGL backend.
gtk	Use gdk-pixbuf from x11-libs/gtk+ as image rendering backend

cogl

gles2	Enable OpenGL ES 2.0 support
kms	Enable KMS support.
pango	Build cogl-pango library for x11-libs/pango integration

coin

exceptions	Compile with C++ exceptions
man	Build and install man pages
qthelp	Build API documentation in QtHelp format
simage	Texture loading via media-libs/simage library

dav1d

10bit	Add support for building 10-bit and 12-bit AV1.
8bit	Add support for decoding 8-bit AV1.
asm	Enable custom assembly for faster decoding.

devil

allegro	Add support for Allegro
nvtt	Add support for media-gfx/nvidia-texture-tools

esdl

image	Enable image support

faad2

digitalradio	Digital Radio Mondiale (warning: disables other decoders)

flickcurl

raptor	Use media-libs/raptor for proper RDF serializing

fontconfig-infinality

nyx	Additional style using croscorefonts

freetype

adobe-cff	Use Adobe CFF as default font-renderer
bindist	Disable ClearType support (see http://freetype.org/patents.html)
brotli	Enable brotli decompression support via app-arch/brotli
bzip2	Support bzip2 compressed PCF fonts.
cleartype_hinting	New bytecode hinting mode for TrueType fonts that activates subpixel hinting (a.k.a. ClearType hinting) by default
fontforge	Install internal headers required for TrueType debugger in media-gfx/fontforge (built with USE=truetype-debugger)
harfbuzz	Use media-libs/harfbuzz for auto-hinting OpenType fonts. WARNING: may trigger circular dependencies!
infinality	Enable infinality options for improved LCD filtering
utils	Install utilities and examples from ft2demos

freeverb3

forcefpu	Disable assembly code
plugdouble	Build plugins in double precision mode (default is float)

ganv

fdgl	Use experimental force-directed graph layout

gd

webp	Enable support for the webp format

gegl

lensfun	Enable support for media-libs/lensfun.
umfpack	Enable sparse solving via sci-libs/umfpack.

gmtk

dconf	Enable support for gnome-base/dconf

grilo

network	Enable network access for media discovery using net-libs/libsoup
playlist	Enable support for playlists through dev-libs/totem-pl-parser

gst-plugins-bad

bzip2	Enable bzip2 encoder/decoder plugin
egl	Enable EGL support
gles2	Enable GLES2 support

gst-plugins-base

X	Enable ximagesink and xvimagesink plugins; build GLX platform support if USE=opengl is enabled; build x11 windowing system support if USE=egl is enabled
egl	Enable EGL platform support
gbm	Enable Graphics Buffer Manager based EGL windowing system support (requires egl and at least one of gles or opengl)
gles2	Enable OpenGL library and plugin via GLESv2 API (requires egl)
ivorbis	Enable integer based vorbis decoder
opengl	Enable OpenGL library and plugin via desktop OpenGL API
pango	Enable pango GStreamer plugin
wayland	Enable Wayland EGL windowing system support (requires egl and at least one of gles2 or opengl)

gstreamer

orc	Disable some PaX memory protections to allow plugins that use dev-lang/orc for runtime optimization to be used on hardened PaX systems
unwind	Enable sys-libs/libunwind usage for better backtrace support in leaks tracer module

harfbuzz

glib	Compile with GLib Unicode support
graphite	Use graphite to render complex non-Roman writing systems

imlib2

X	Use the X window system
bzip2	Bzip2 loader support
gif	Gif image loader support
jpeg	Jpeg image loader support
mp3	ID3 loader support
png	PNG image loader support
shm	Use MIT shared memory support for X image transfer
tiff	TIFF image loader support
webp	WEBP image loader support
zlib	Zlib loader support

leptonica

utils	Install command-line utilities

libafterimage

shaping	Use MIT shaped X windows extention.
shm	Use MIT shared memory extention for X image transfer.

libass

harfbuzz	Enables OpenType shaping via media-libs/harfbuzz.

libbdplus

aacs	Add support for decryption of AACS

libbluray

aacs	Add support for decryption of AACS
bdplus	Use media-libs/libbdplus for BD+ decryption
java	Add support for BD-J
utils	Install command-line utilities and examples

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.

libepoxy

egl	Enable EGL support.

libextractor

apparmor	Enable apparmor support using sys-libs/libapparmor
archive	Enable archive support using app-arch/libarchive
gsf	Enable OLE2 (MS Office) plug-in support using gnome-extra/libgsf
midi	Enable MIDI support through media-libs/libsmf

libffado

test-programs	Install standalone test programs

libggi

vis	Enables sparc vis support for libggi

libgphoto2

serial	Enable serial port support

libgpod

gtk	Enable ArtworkDB support

libgroove

chromaprint	Enable audio fingerprinting using media-libs/chromaprint.
loudness	Enable loudness detection according to the EBU R128 standard using media-libs/libebur128.
sound	Enable audio playing.

liblastfm

fingerprint	Build the lastfm-fingerprint library

libmp4v2

utils	Install command-line utilities

libmypaint

gegl	Add support for media-libs/gegl

libopenglrecorder

openh264	Enable H.264 support using media-libs/openh264
vpx	Enable VP8/VP9 codec support via media-libs/libvpx

libpagemaker

tools	Build command line file format conversion tools

libplacebo

glslang	Use dev-util/glslang to compile GLSL
lcms	Add support for color management via media-libs/lcms
shaderc	Use media-libs/shaderc to compile GLSL
vulkan	Add support for the vulkan graphics API

libpng

apng	support unofficial APNG (Animated PNG) spec

libpng-compat

apng	support unofficial APNG (Animated PNG) spec

libprojectm

gles2	Provide support for OpenGL ES 2 and 3

libsdl

joystick	Control joystick support (disable at your own risk)
sound	Control audio support (disable at your own risk)
tslib	Build with tslib support for touchscreen devices
video	Control video support (disable at your own risk)

libsdl2

gles2	include OpenGL ES 2.0 support
haptic	Enable the haptic (force feedback) subsystem
joystick	Control joystick support (disable at your own risk)
kms	Build the KMSDRM video driver
sound	Control audio support (disable at your own risk)
tslib	Build with tslib support for touchscreen devices
video	Control video support (disable at your own risk)
vulkan	Enable Vulkan support

libtgvoip

dsp	Enable signal processing (echo cancellation, noise suppression, and automatic gain control)

libvisio

tools	Build conversion tools

libvpx

highbitdepth	Enable 10 and 12 bit support for VP9.
postproc	Enable additional post processing filters
svc	Enable spatial-svc support (experimental)

libwebp

swap-16bit-csp	Enable byte swapping for 16 bit colorspace

libyami

dmabuf	Enable dma_buf buffer sharing.
egl	Enable EGL support.
md5	Add support for generating md5 sums for each frame.
v4l	Add support for V4L2 hardware codecs.

libzmf

tools	Build conversion tools

lilv

dyn-manifest	Add LV2 Dynamic Manifest support. See http://lv2plug.in/ns/ext/dynmanifest/

lsp-plugins

lv2	build lv2 plugins

lv2

plugins	Enables examples plugins.

lvtk

gtk2	Enable x11-libs/gtk+:2 based GUI support
tools	Compile and install ttl2c tool

mesa

classic	Build drivers based on the classic architecture.
d3d9	Enable Direct 3D9 API through Nine state tracker. Can be used together with patched wine.
dri3	Enable DRI3 support.
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.
gles1	Enable GLESv1 support.
gles2	Enable GLESv2 support.
libglvnd	Use libglvnd for dispatch.
llvm	Enable LLVM backend for Gallium3D.
lm-sensors	Enable Gallium HUD lm-sensors support.
opencl	Enable the Clover Gallium OpenCL state tracker.
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
valgrind	Compile in valgrind memory hints
vdpau	Enable the VDPAU acceleration interface for the Gallium3D Video Layer.
vulkan	Enable Vulkan drivers
vulkan-overlay	Build vulkan-overlay-layer which displays Frames Per Second and other statistics
wayland	Enable support for dev-libs/wayland
xa	Enable the XA (X Acceleration) API for Gallium3D.
xvmc	Enable the XvMC acceleration interface for the Gallium3D Video Layer.

mlt

compressed-lumas	Compress the luma files in png.
frei0r	Build the module for media-plugins/frei0r-plugins
kdenlive	Build support for kde-apps/kdenlive
lua	Build SWIG bindings for Lua
melt	Build the melt commandline tool
opencv	Build motion tracking module using media-libs/opencv
python	Build SWIG bindings for Python
rtaudio	Builds rtaudio consumer for native audio support on multiple platforms.
ruby	Build SWIG bindings for Ruby
vidstab	Enabled video stabilization with media-libs/vidstab.

netpbm

rle	Build converters for the RLE format (utah raster toolkit)

opencv

contrib	Install user contributed scripts from opencv_contrib (Experimental!)
contribcvv	CVV module requires Qt5
contribdnn	DNN module contrib requires tiny dnn
contribhdf	HDF module requires sci-libs/hdf5
contribsfm	SFM module requires eigen, gflags, and glog
contribxfeatures2d	Enables xfeatures2d and autodownload of samples in contrib
cuda	Enable NVIDIA Cuda computations support (Experimental!)
dnnsamples	Download dnn caffeemodel samples
download	Enable download during cmake configure
eigen	Enable usage of dev-cpp/eigen for computations
features2d	Enable features2d module
gdal	Enable support for sci-libs/gdal library
gflags	Use Google's C++ argument parsing library
glog	Use Google's C++ loggin library
gtk3	Enable x11-libs/gtk+:3 support
opencl	Add support for OpenCL
opencvapps	Enable compilation with opencvapps
tesseract	Use Google's OCR Engine
testprograms	Build and install programs for testing OpenCV (performance)
vtk	Build new 3D visualization module viz based on sci-libs/vtk

openh264

plugin	Install the Gecko Media Plugin (GMP) for use with Mozilla packages
utils	Install the CLI encoder and decoder utilities

openimageio

color-management	Enable color management via media-libs/opencolorio
dicom	Enable DICOM medical image file support via sci-libs/dcmtk
field3d	Enable f3d file (write) support via media-libs/Field3D
opencv	Enable OpenCV support via media-libs/opencv
ptex	Enable Ptex texture mapping system file support via media-libs/ptex

opensubdiv

cuda	Enable NVIDIA CUDA Toolkit support through dev-util/nvidia-cuda-toolkit.
opencl	Enable OpenCL support through virtual/opencl.
ptex	Adds support for faster per-face texture mapping through media-libs/ptex.
tbb	Enable multithreading with the Intel Threads Building Blocks through dev-cpp/tbb.

opus

custom-modes	Enable non-Opus modes, e.g. 44.1 kHz and 2^n frames

opusfile

fixed-point	Enable fixed-point arithmetic operations
float	Enable floating point arithmetic operations
http	Enable http connections

osl

partio	Use media-libs/partio
qt5	Build the osltoy binary

phonon

designer	Install plugin for dev-qt/designer
vlc	Install VLC Phonon backend

phonon-gstreamer

network	Enable network streaming support via libsoup

portmidi

test-programs	Install various example programs

qtav

gui	Build a video player gui

quvi

json	Enable support for JSON output

raptor

json	Enable support for JSON parsing

raspberrypi-userland-bin

hardfp	Use armv6 hardfp ABI

sdl-mixer

fluidsynth	Use media-sound/fluidsynth for MIDI support
midi	basic support for MIDI files
mod	basic support for MOD files
playtools	Install playwave and playmus tools (useful for testing)
smpeg	Use media-libs/smpeg for MP3 support
wav	support WAVE files

sdl-sound

physfs	Enable support for various formats through dev-games/physfs.

sdl2-image

webp	support loading WEBP images

sdl2-mixer

fluidsynth	Use media-sound/fluidsynth for MIDI support
midi	basic support for MIDI files
mod	basic support for MOD files
playtools	Install playwave and playmus tools (useful for testing)
smpeg	Use media-libs/smpeg for MP3 support
tremor	enable OGG Vorbis music via libtremor
wav	support WAVE files

sge

image	enable sdl-image support

spandsp

fixed-point	Enable fixed point support

speex

utils	Enables speex commandline utilities (speexenc, speexdec).
vbr	Enable VBR support.

svgalib

kernel-helper	Build the helper kernel module

tremor

low-accuracy	enable 32bit only multiply operations

urt

tools	Install tools

vigra

valgrind	Enable valgrind in make check

vulkan-loader

layers	Include the vulkan layers

waffle

egl	Enable EGL support
gbm	Enable support for the Generic Buffer Manager (gbm)
wayland	Enable Wayland support

webvfx

doc	Install doxygen developer documentation

x264

interlaced	enable interlaced encoding support, this can decrease encoding speed by up to 2%
opencl	Add support for OpenCL.
pic	disable optimized assembly code that is not PIC friendly

x265

10bit	Add support for producing 10bits HEVC.
12bit	Add support for producing 12bits HEVC.
asm	Enable x86_64 assembly optimizations.
numa	Build with support for NUMA nodes.
pic	Disable optimized assembly code that is not PIC friendly
power8	Enable support for Power 8 assembly optimizations.

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.
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.
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.
vdr	Build the VDR plugin
vidix	Enable support for vidix video output.
vis	Adds support for SIMD optimizations for UltraSPARC processors.
vpx	Enable VP8 codec support via media-libs/libvpx.
xvmc	Enable support for XVideo Motion Compensation (accelerated mpeg playback).

xvid

pic	disable optimized assembly code that is not PIC friendly

zita-resampler

tools	Install zresample and zretune tools

media-plugins

alsa-plugins

arcam_av	Enables Arcam AV control plugin
mix	Enables upmix and vdownmix plugin
usb_stream	Enables usb_stream plugin

audacious-plugins

ampache	Support controlling audacious via www-apps/ampache
bs2b	Enable Bauer Bauer stereophonic-to-binaural headphone filter
cue	Support CUE sheets using the libcue library
fluidsynth	Support FluidSynth as MIDI synth backend
gme	Support various gaming console music formats
gtk	Build with GTK interface instead of Qt5
http	Support HTTP streams through neon
qtmedia	Enable playback via dev-qt/qtmultimedia
scrobbler	Build with scrobbler/LastFM submission support
sid	Build with SID (Commodore 64 Audio) support
soxr	Build with SoX Resampler support
speedpitch	Enable speed/pitch effects
streamtuner	Build the streamtuner plugin

calf

experimental	Enable experimental features/plugins
lv2	Add support for Ladspa V2

frei0r-plugins

facedetect	Enables building of facedetect plugin, which depends on media-libs/opencv
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

chromaprint	Enable Chromaprint support
daap	Enable dmap support through net-libs/libdmapsharing
flickr	Enable Flickr support
freebox	Build support for viewing TV channels using Freebox
gnome-online-accounts	Enable net-libs/gnome-online-accounts support
thetvdb	Build support for thetvdb.com
tracker	Build support for content discovery using the app-misc/tracker indexer
youtube	Build support for YouTube content discovery using dev-libs/libgdata

gst-plugins-gtk

egl	Enable EGL platform usage
gles2	Enable gtkglsink OpenGL sink based on GLESv2 API
opengl	Enable gtkglsink OpenGL sink based on desktop OpenGL API

gst-plugins-libav

libav	Use bundled ffmpeg to support systems using media-video/libav globally instead of media-video/ffmpeg

gst-plugins-meta

http	Enable http streaming via net-libs/libsoup
libvisual	Enable visualization effects via media-libs/libvisual
vpx	Enables vp8 codec support using libvpx, required to play some HTML5 videos

gst-plugins-vaapi

drm	Enable DRM renderer
egl	Enable EGL support
gles2	Enable GLESv2 and GLESv3 support

hexter

gtk2	Enable x11-libs/gtk+:2 based GUI

imlib2_loaders

eet	Enable Eet image loader
xcf	Enable XCF image loader

ir_lv2

tools	Build convert4chan tool

mythplugins

cdr	Allows MythMusic to burn CD-Rs
exif	Allows MythGallery to read EXIF data from photos
fftw	Adds visual effects to MythMusic when playing back music
hls	HTTP Live Streaming support
mytharchive	Allows you to archive recorded content to CD or DVD
mythbrowser	Adds a web browser within MythTV
mythgallery	Adds a picture viewing gallery within MythTV
mythgame	Adds a frontend to various ROM emulators within MythTV
mythmusic	Adds the ability for MythTV to act as a music player
mythnetvision	Adds the ability to view netvision devices within MythTV
mythnews	Adds a news viewer within MythTV
mythweather	Adds weather information within MythTV
mythzmserver	Build mythzmserver daemon needed by zoneminder on LAN
mythzoneminder	Adds support for zoneminder (requires active mythzmserver daemon on LAN).
raw	Allows MythGallery to view photos saved in RAW format

vdr-burn

dvdarchive	DMH DVD - Archive

vdr-cdplayer

cdparanoia	Enable cdparanoia (audio CD ripper) support

vdr-dvbapi

dvbcsa	use media-libs/libdvbcsa free implementation of the DVB Common Scrambling Algorithm

vdr-epgsearch

conflictcheckonly	install the "conflictcheckonly" vdr-plugin
epgsearchonly	install the "epgsearchonly" vdr-plugin
quicksearch	install the "quicksearch" vdr-plugin
tre	Add support for unlimited fuzzy searching with help of dev-libs/tre library

vdr-streamdev

client	Compile the VDR plugin vdr-streamdev-client that acts like a dvb-budget card
server	Compile the VDR plugin vdr-streamdev-server that allows remote systems to access the DVB cards used for the local VDR

vdr-vdrmanager

stream	Add support for streaming Video to Android client

vdr-weatherng

dxr3	enables lower osd color depth for dxr3 cards

vdr-xineliboutput

bluray	Enable BluRay metadata support through media-libs/libbluray
cec	Enable CEC support through dev-libs/libcec
libextractor	Use media-libs/libextractor to gather files' metadata in media-player
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

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

tucnak

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

geotiff	Install geotiff support. Allows using USGS DRG topo maps or other types of geotiff mapes/images

media-sound

abcde

aiff	Enable support for Audio Interchange File Format (AIFF) output encoding
id3tag	Support ID3, ID3v2 tagging of audio files
mac	Enable support for Monkey's 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

alsa-utils

bat	install basic audio tester (BAT) util
libsamplerate	install utils that use libsamplerate (e.g. alsaloop)
ncurses	install utils that use ncurses (e.g. alsamixer)

alsaplayer

id3tag	Enables ID3 tagging with id3tag library

amsynth

dssi	Enable support for DSSI Soft Synth Interface
lv2	Add support for Ladspa V2

apulse

sdk	Install PulseAudio headers and pkg-config files. Be aware apulse is not a full PulseAudio replacement by design and some functionality may be missing.

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

phonehome	contact ardour.org at startup for new announcements

ario

idle	Enable experimental support for MPD's idle command to reduce bandwidth and cpu usage, requires MPD 0.14

asunder

mac	Support for creation of Monkey's Audio files (APE)

audacious

gtk	Build with GTK interface instead of Qt5

audacity

id3tag	Enables ID3 tagging with id3tag library
lv2	Add support for Ladspa V2
midi	Enables MIDI support
portmixer	Enable the internal portmixer feature
sbsms	Enables sbsms library support for slower, more accurate pitch and tempo changing
soundtouch	Enables soundtouch library support for pitch and tempo changing
twolame	Enables twolame support (MPEG Audio Layer 2 encoder)
vamp	Enables vamp plugins support (Audio analysing plugins)
vst	Enable VST plugin support

audiotools

cue	Enable CUE sheet support
dvda	Enable DVD-Audio support
twolame	Enable twolame support (MPEG Audio Layer 2 encoder)

beets

badfiles	Validate MP3 & FLAC files
chromaprint	Enable support for acoustic fingerprinting plugin using media-libs/chromaprint
discogs	Enable support for the discogs API plugin
ffmpeg	Enable support for the convert plugin to transcode files via media-video/ffmpeg
lastfm	Enable support for importing personal last.fm playcounts and music genres from last.fm tags
mpd	Enable support for media-sound/mpd server emulation and statistic gathered from media-sound/mpd
replaygain	Enable support for Replay Gain metadata calculation during import
thumbnail	Enable album thumbnails generation
webserver	Enable embedded webserver support through dev-python/flask

bluez-alsa

hcitop	Enable top-like monitoring tool for HCI
ldac	Enable support for AOSP media-libs/libldac dispatcher
ofono	Enable ofono elephony support

cadence

a2jmidid	Enables support for legacy ALSA sequencer applications in JACK MIDI system

cantata

cdio	Use dev-libs/libcdio-paranoia for CD support (instead of cdparanoia)
http-server	Enable internal HTTP server to play non-MPD files
replaygain	Enable ReplayGain support, for relative volume adjustments
streaming	Enable playback of MPD HTTP streams using LibVLC (media-video/vlc)

clementine

box	Enable filesharing via Box.com
dropbox	Enable Dropbox support
googledrive	Enable Google Drive support
lastfm	Use liblastfm for fetching song info, scrobbling and radio streams
moodbar	Enable moodbar support
projectm	Build with ProjectM visualization
seafile	Enable support for seafile: a file sync service
skydrive	Enable Skydrive support
wiimote	Enable support for Wii remote

cmus

cdio	Use libcdio for CD support
discid	Enable reading the ID of the inserted CD
elogind	Enable MPRIS support via sys-auth/elogind
pidgin	Install support script for net-im/pidgin
systemd	Enable MPRIS support via sys-apps/systemd
tremor	Use libivorbis from media-libs/tremor instead of media-libs/libvorbis

csound

beats	Build the beats score frontend
chua	Build the chua opcodes
double-precision	Use double-precision floating point for audio samples
dssi	Build the DSSI opcodes
fluidsynth	Build the fluidsynth opcodes
image	Build the image opcodes
keyboard	Build Virtual MIDI keyboard
linear	Build the linear algebra Opcodes
portmidi	Build the PortMIDI I/O module
samples	Install the HRTF datafiles for use with hrtfmove, hrtfmove2, hrtfstat, hrtfearly, and hrtfreverb
stk	Build the stk opcodes
utils	Build stand-alone executables for utilities that can also be used via `csound -U`
websocket	Build the websocket opcode

darkice

aacplus	AAC+ encoding via media-libs/libaacplus
twolame	Build with twolame support

deinvert

liquid	improve sound quality using net-libs/liquid-dsp
wav	wav file support using media-libs/libsndfile

denemo

alsa	Enable alsa support through media-libs/alsa-lib
aubio	Enable media-libs/aubio support
fluidsynth	Enable Fluidsynth MIDI software synthesis using media-sound/fluidsynth
jack	Enable jack support through virtual/jack
portaudio	Enable support for media-libs/portaudio
portmidi	Enable support for the media-libs/portmidi backend
rubberband	Enable support for media-libs/rubberband