* config/srclist.txt: Add glibc bug 1245.

* config/srclist.txt: Add glibc bug 1245.

* lib/regexec.c (set_regs): Don't alloca with an unbounded size.

alloca modernization/simplification for regex.
* lib/regex.c: Remove portability cruft for alloca.  This no longer
needs to be at the start of the file, and can be moved into
regex_internal.h and simplified.
* lib/regex_internal.h: Include <alloca.h>.
(__libc_use_alloca) [!defined _LIBC]: New macro.
* lib/regexec.c (build_trtable): Remove "#ifdef _LIBC",
since the code now works outside glibc.