Upgrade to =sys-libs/uclibc-ng-1.0.22

Title: Upgrade to =sys-libs/uclibc-ng-1.0.22
Author: Anthony G. Basile <blueness@gentoo.org>
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Posted: 2017-02-10
Revision: 1
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There have been two major changes in uclibc-ng which need special
attention when upgrading. Version 1.0.19 restructured the breakout
libraries, libcrypt.so.0, libdl.so.0, and friends.  The functions in
those libraries are now included in libuClibc-  Version
1.0.21 and above removed libc support for obstack, expecting packages to
use their bundled GNU lib code. Both changes require special upgrade
procedures which we outline below: 

0. Because of changes in the library structure in previous versions,
make sure you are working with 1.0.19 and rebuild world using

    emerge -e @world

This will make sure all the executables link directly against libc.so.0
(as reported by `readelf -d`) rather than via symlinks like libdl.so.0
-> libc.so.0.  Then upgrade from 1.0.19 to 1.0.20 without symlink-compat:

    USE="-symlink-compat" emerge =sys-libs/uclibc-ng-1.0.20

1. Get rid of the obstack.h header since it's used by configure scripts
to look for function prototypes and macros.

    mv /usr/include/obstack.h ~

2. We also need to force the use of any bundled gnu lib code.  We can do
this by removing the definition of _GNU_OBSTACK_INTERFACE_VERSION from

    cp /usr/include/gnu-versions.h ~
    sed -i -e '/#define _GNU_OBSTACK/d' /usr/include/gnu-versions.h

3. We need to tell stdio.h that __UCLIBC_HAS_OBSTACK__ is false.  We do
this via the uClibc_config.h file.

    cp /usr/include/bits/uClibc_config.h ~
    sed -i -e '/__UCLIBC_HAS_OBSTACK__/ s/1/0/' \

4. To be safe, you may want to back up your entire /lib directory so
you can fall back should something go wrong:

    cp -a /lib /lib.bak

5. Now when we rebuild @world, all packages will use their bundled
obstack code rather than depending on libc to provide it.

    ac_cv_func_obstack_vprintf=no emerge --keep-going --exclude \
     sys-libs/uclibc-ng -e @world

6. Finally update uclibc-ng to the latest

    emerge =sys-libs/uclibc-ng-1.0.22

7. For good measure, rebuild the entire system

    emerge —e @world