build: fix for Wayland headers not in standard include dirs.
build: fix for Wayland headers not in standard include dirs.

Fix build when Wayland headers don't live in plain system include dirs
like /usr/include but rather in /usr/include/wayland for instance.

Original patch written by Dominique Leuenberger <dimstar@opensuse.org>

https://bugzilla.gnome.org/show_bug.cgi?id=712282

CapOM/gstreamer-vaapi,GStreamer/gstreamer-vaapi,gbeauchesne/gstreamer-vaapi,gbeauchesne/gstreamer-vaapi,GStreamer/gstreamer-vaapi,CapOM/gstreamer-vaapi,ceyusa/gstreamer-vaapi,CapOM/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,ceyusa/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,gbeauchesne/gstreamer-vaapi