minigbm: Move c99 flag from CPPFLAGS to CFLAGS

It has nothing to do with the preprocessor.

BUG=none
TEST=builds

Change-Id: Ib5c851b0127d36bf52cce1e5c81cfed0eb3b541d
Reviewed-on: https://chromium-review.googlesource.com/415112
Commit-Ready: Gurchetan Singh <gurchetansingh@chromium.org>
Tested-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
1 file changed