grub-1.99: fix configure error

grub-1.99: fix configure error

This commit deals with this configure error.

configure:20306: checking whether `ccache i586-poky-linux-gcc  -m32
-march=core2 -msse3 -mtune=generic -mfpmath=sse
--sysroot=/builddisk/build/build0/tmp/sysroots/emenlow' generates calls
to `__enable_execute_stack()'
configure:20320: ccache i586-poky-linux-gcc  -m32    -march=core2 -msse3
-mtune=generic -mfpmath=sse
--sysroot=/builddisk/build/build0/tmp/sysroots/emenlow -O2 -pipe -g
-feliminate-unused-debug-types -Wall -W -Wshadow -Wpointer-arith
-Wmissing-prototypes -Wundef -Wstrict-prototypes -g -falign-jumps=1
-falign-loops=1 -falign-functions=1 -mno-mmx -mno-sse -mno-sse2
-mno-3dnow -mfpmath=387 -fno-dwarf2-cfi-asm -m32 -fno-stack-protector
-mno-stack-arg-probe -Werror -Wno-trampolines -falign-loops=1 -S
conftest.c
conftest.c:308:6: error: no previous prototype for 'g'
[-Werror=missing-prototypes]
cc1: all warnings being treated as errors
configure:20323: $? = 1
configure:20327: error: ccache i586-poky-linux-gcc  -m32    -march=core2
-msse3 -mtune=generic -mfpmath=sse
--sysroot=/builddisk/build/build0/tmp/sysroots/emenlow failed to produce
assembly code

Signed-off-by: Nitin A Kamble <nitin.a.kamble@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>