Pointer constraint is ignored before the first click on the surface in Warcraft III running in wine-wayland

Alexandros’s old Wine wayland branch uses pointer constraints and wp_viewporter to expose the same feature as mode switches but just for the one fullscreen surface.

Since the crash in #823 (closed) got resolved, the pointer constraint is still not applied correctly until the first click on the surface, before that the software pointer will appear to be stuck to its last position when the pointer is outside of the surface, and will teleport to the new position once it is back inside, which is not the expected behaviour when using pointer constraints.