Add support to turn on the "obsolete" arm-rtems4.11 target.

This indicate a bug in the gcc patches that should be making
arm-rtems4.11 the standard EABI tools for RTEMS.

source-builder/config/gcc-4.7-1.cfg

@@ -148,6 +148,9 @@ Source22: ftp://ftp.gnu.org/gnu/gmp/gmp-%{gmp_version}.tar.bz2
     %{?with_plugin:--enable-plugin}%{!?with_plugin:--disable-plugin} \
     --enable-newlib-io-c99-formats \
     %{?with_iconv:--enable-newlib-iconv} \
+%if %{enable_obsolete}
+    --enable-obsolete \
+%endif
     --enable-languages="$languages"
 
 %if "%_host" != "%_build"