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="Harold Grovesteen"

 reporter_url="http://sourceware.org/ml/crossgcc/2009-11/msg00052.html"

 reporter_comment=""