sys-libs/glibc: run fixincludes in pkg_postinstHEADmaster

We enabled fixincludes for a window between GCC 13 and whatever the just
released version of glibc was at the time to cover Float128 changes. We
then turned it off again when it was (mostly) no longer needed.

(Though arguably it was/still is needed for some upgrade paths or combinations
and maybe we should reconsider that given we now have a proper solution here
to "defanging" fixincludes (as it turns out we were kind of using it wrong,
see bug #30701)).

Anyway, for any glibc installed during that window, a fixincludes'd pthread.h
would've been installed to the include-fixed directory, which then becomes
a cached stale copy when the rest of glibc changes like:
```
--- pthread.h-fixincludes       2024-12-12 06:49:06.918089635 +0000
+++ /usr/include/pthread.h      2024-12-06 16:49:09.306028087 +0000
[...]
@@ -232,7 +223,7 @@
    the thread in *THREAD_RETURN, if THREAD_RETURN is not NULL.  */
 extern int pthread_tryjoin_np (pthread_t __th, void **__thread_return) __THROW;

-# ifndef __USE_TIME_BITS64
+# ifndef __USE_TIME64_REDIRECTS
```
because the guards no longer match up with the rest of glibc.

The fix is for us to refresh fixincludes using `mkheaders` (if available)
which we weren't installing until recently (7d99be77433bf10fb0ce6fc99c7b40de700ed650)
in pkg_postinst for sys-libs/glibc. We will likely need to add similar
logic into linux-headers at least too. I am considering adding such an update
to gcc-config too.

Note that we also have to cover the case where mkheaders isn't available
*but* a cached broken pthread.h exists, so if mkheaders doesn't exist, but
pthread.h does in include-fixed, we move that away to .bak.

Bug: https://gcc.gnu.org/PR20166
Bug: https://gcc.gnu.org/PR94089
Bug: https://gcc.gnu.org/PR107059
Bug: https://gcc.gnu.org/PR118009
Bug: https://bugs.gentoo.org/30701
Bug: https://bugs.gentoo.org/933282
Tested-by: Matt Jolly <kangie@gentoo.org>
Signed-off-by: Sam James <sam@gentoo.org>

0 files changed, 0 insertions, 0 deletions