cc/gcc: enable plugins if needed

Enabling plugins in binutils is not enough, and gcc also
needs to be ./configured with --enable-plugins, although
this is not documented anywhere... :-/

Reported-by: karthik duraisami <kdconstant@hotmail.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 #!/bin/sh

 call_to=@@DEFAULT_LD@@

 case "${CTNG_LD_IS}" in

     bfd)    call_to=bfd;;

     gold)   call_to=gold;;

 esac

 exec "${0}.${call_to}" "$@"

 exit $?