This script checks that header files in a given directory do not miss
dependencies when included on their own, do not conflict and accept being
compiled with the strictest possible flags.
It is too slow at the moment to be automatically executed by test-build.sh
and should be run voluntarily (like check-git-log.sh and friends) after
making changes to exported header files.
Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>