build: Add missing Mir includes for gtk-doc
build: Add missing Mir includes for gtk-doc

If we don't specify the files, gtk-doc won't find the symbols even if
they are documented.

Distrotech/clutter,GNOME/clutter,jigpu/clutter,jigpu/clutter,Distrotech/clutter,GNOME/clutter,jigpu/clutter,GNOME/clutter,jigpu/clutter,GNOME/clutter,Distrotech/clutter,GNOME/clutter,jigpu/clutter,Distrotech/clutter,jigpu/clutter,Distrotech/clutter,Distrotech/clutter