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>

 # Default test suite configuration

 # Default DejaGnu configuration

 DG_TOOLNAME = gcc

 DG_TARGET_HOSTNAME = 127.0.0.1

 DG_TARGET_USERNAME = root

 # Default tests

 DG_C_TESTS = 

 DG_CPP_TESTS =