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

 CT_EXPERIMENTAL=y

 CT_LOCAL_TARBALLS_DIR="${HOME}/src"

 CT_SAVE_TARBALLS=y

 CT_LOG_EXTRA=y

 CT_ARCH_mips=y

 CT_TARGET_VENDOR="malta"

 CT_KERNEL_linux=y

 CT_KERNEL_V_2_6_38_8=y

 CT_BINUTILS_V_2_21_1a=y

 CT_CC_V_4_4_6=y

 # CT_CC_GCC_USE_GRAPHITE is not set

 CT_LIBC_EGLIBC_V_2_13=y

 CT_DEBUG_gdb=y

 # CT_GDB_GDBSERVER_STATIC is not set

 CT_GDB_V_7_2a=y

 CT_GMP_V_5_0_1=y

 CT_MPFR_V_3_0_0=y

 CT_TEST_SUITE_GCC=y