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 -durN gcc-4.2.1.orig/boehm-gc/include/gc.h gcc-4.2.1/boehm-gc/include/gc.h

--- gcc-4.2.1.orig/boehm-gc/include/gc.h	2006-09-18 20:45:08.000000000 +0200

+++ gcc-4.2.1/boehm-gc/include/gc.h	2007-08-03 20:33:00.000000000 +0200

@@ -502,7 +502,7 @@

 #if defined(__linux__) || defined(__GLIBC__)

 # include <features.h>

 # if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1 || __GLIBC__ > 2) \

-     && !defined(__ia64__)

+     && !defined(__ia64__) && !defined(__UCLIBC__)

 #   ifndef GC_HAVE_BUILTIN_BACKTRACE

 #     define GC_HAVE_BUILTIN_BACKTRACE

 #   endif