Don't check for -Wl,{option} support.

Not all AC_WIRESHARK_LDFLAGS_CHECK flags are -Wl,{option} flags, so
don't check for that first.  If we want to check for specific compilers
and linkers, we should do that, not for -Wl,{option} support.

Change-Id: Ib9581d4a1573a1ffa2493ce08e6d5845d2601352
Reviewed-on: https://code.wireshark.org/review/2755
Reviewed-by: Guy Harris <guy@alum.mit.edu>