libc/eglibc: fix missing LIBC_TRY_CC_OPTION definition (eglibc 2.15)

Upstream SVN is currently broken:
http://www.eglibc.org/svn/branches/eglibc-2_15/libc/

LIBC_TRY_CC_OPTION macro is not defined in aclocal.m4.
This patch fix the configure script.

Once upstream branch will be fixed this patch could be reverted.

Related patch (committed to eglibc trunk):
Use autoconf macro for testing compiler options with empty input
http://sourceware.org/ml/libc-alpha/2012-03/msg00816.html

Signed-off-by: Matthieu Crapet <mcrapet@gmail.com>

diff -r 1f6c8e4b2b92 -r d10afc5bcc25
patches/eglibc/2_15/110-aclocal-LIBC_TRY_CC_OPTION.patch

 diff -ru gdb-6.8.orig/bfd/sysdep.h gdb-6.8/bfd/sysdep.h

 --- gdb-6.8.orig/bfd/sysdep.h	2007-07-03 16:26:42.000000000 +0200

 +++ gdb-6.8/bfd/sysdep.h	2011-08-21 13:33:47.000000000 +0200

 @@ -131,7 +131,7 @@

  extern PTR realloc ();

  #endif

 -#if !HAVE_DECL_STPCPY

 +#if !HAVE_DECL_STPCPY && !defined(stpcpy)

  extern char *stpcpy (char *__dest, const char *__src);

  #endif