build: Fix compilation when using GLES
build: Fix compilation when using GLES

Some headers do not define APIENTRY or APIENTRYP, define them in this
case. Compile some headers/function that are only used by the ARB fp
renderer.

lubosz/clutter-gst,GNOME/clutter-gst,GNOME/clutter-gst,skinkie/clutter-gst,ystreet/clutter-gst,ystreet/clutter-gst,lubosz/clutter-gst,lubosz/clutter-gst,ystreet/clutter-gst,GNOME/clutter-gst,skinkie/clutter-gst,GNOME/clutter-gst,ystreet/clutter-gst,skinkie/clutter-gst