Headers from lib/ depend on drm uapi headers. Since we started
embedding them, let's make sure to pull them first. We still depend on
libdrm in places, we don't want the system headers from libdrm to be
included prior to the embedded ones.
v2: Fix debugger/overlay (Lionel)
v3: More fixes in lib/tests (Lionel)
Signed-off-by: Lionel Landwerlin <firstname.lastname@example.org>
Reviewed-by: Chris Wilson <email@example.com>