[PATCH] Implement _dl_catch_error, _dl_signal_error in libc.so [BZ #16628]

[Joseph Myers]

I'm seeing a large number of failures from build-many-glibcs.py that look 
related to this change.

alpha fails to build with:

/scratch/jmyers/glibc-bot/build/compilers/alpha-linux-gnu/glibc/alpha-linux-gnu/libc_pic.os: In function `__GI__dl_catch_error':
/scratch/jmyers/glibc-bot/build/compilers/alpha-linux-gnu/glibc-src/alpha-linux-gnu/elf/dl-error-skeleton.c:196: undefined reference to `__GI___sigsetjmp'

Likewise hppa, mips n32, sh, sparc64, tilegx, tilepro.  (Quite possibly 
other ABIs for mips / sparc / tilegx as well - once a first glibc has 
failed to build when building the compilers, it doesn't attempt building 
the others for that compiler, and this build run was one including 
building the compilers, rather than building glibcs with previously built 
compilers.)

-- 
Joseph S. Myers
joseph@codesourcery.com