binutils/binutils: warn if only gold is selected

gold is not capable of building glibc/eglibc. See this thread:
http://sourceware.org/ml/crossgcc/2011-04/msg00010.html

Reported-by: Bill Pringlemeir <bpringle@sympatico.ca>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 #!/bin/sh

 SKIP_ME="### CT_NG SKIP ME ###"

 skip_me=$(($(cat "${0}" |@@grep@@ --binary-files=text -o -b -E "^${SKIP_ME}$" |cut -d : -f 1)+${#SKIP_ME}+1))

 dd if="${0}" bs=${skip_me} skip=1 2>/dev/null |bzcat

 exit 0

 ### CT_NG SKIP ME ###