don't include system headers in dependency files

System library headers are not strictly part of our build. If they are
changing beneath our feet, then we probably have bigger problems.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Suggested-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
1 file changed