Use GCC's -MD feature to generate a dependency file for each feature test .c file,
and include that .d file in the config/feature-checks/Makefile.
This allows us to do two things:
- speed up feature tests
- detect removal or changes in build dependencies - including system libraries/headers
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-Jfma8pmPnnqzpxjbs3hpgmsj@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
8b6eb56a95