kbuild: Check if linker supports the -X option

The new alternative `gold' linker in recent binutils doesn't support
the -X option. This breaks allyesconfig builds that have
CONFIG_STRIP_ASM_SYMS enabled. Check if the linker really supports
the option using ld-option.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

diff --cc Makefile
Simple merge