gcc: improved to build with --enable-gnu-unique-object if glibc is the primary libc used by the target

Note:

see: http://gcc.gnu.org/install/configure.html

------------------------------------------------------------------------------
--enable-gnu-unique-object

Tells GCC to use the gnu_unique_object relocation for C++ template static data
members and inline function local statics. Enabled by default for a native
toolchain with an assembler that accepts it and GLIBC 2.11 or above, otherwise
disabled.
------------------------------------------------------------------------------

base/gcc/gcc.conf

@@ -122,6 +122,14 @@ languages="c,c++"
 var_append confopt ' ' "--enable-c99"
 var_append confopt ' ' "--enable-long-long"
 
+# special features when glibc is the primary libc for the target
+if [ "$SDECFG_LIBC" = 'glibc' ]; then
+	# use the gnu_unique_object relocation for C++ template static data
+	# members and inline function local statics
+	var_append confopt ' ' "--enable-gnu-unique-object"
+fi
+
+
 # build prerequisites
 var_append extraconfopt ' ' "--with-gmp=$( pkgprefix -r gmp )"
 var_append extraconfopt ' ' "--with-gmp-lib=$( pkgprefix -r libdir gmp )"