binutils/binutils: add wrapper to gold and ld

When both gold and ld are installed, add a wrapper that calls
to either gold or ld.

In case the wrapper is installed, we also need to symlink ld.bfd
and ld.gold for the core_cc steps.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 reporter_name="Nye Liu"

 reporter_url="http://sourceware.org/ml/crossgcc/2008-10/msg00046.html"

 reporter_comment=""