Makefile: Test compiler for -Wincompatible-function-pointer-types

It seems that the upstream coreboot HOSTCC doesn't support
-Wincompatible-function-pointer-types yet, so we need to add it to the
list of flags that are explicitly checked for compiler support.

BRANCH=none
BUG=none
TEST=none

Change-Id: Iafe724c3908862d4f1623ffa4affc8b82e075792
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/5318537
Reviewed-by: Yu-Ping Wu <yupingso@chromium.org>
1 file changed