At least Doom 64 calls ClipCursor() with identical parameters repeatedly, which seems to cause a considerable overhead. Together with high polling rate mouse input this causes the game to almost freeze while the mouse is being moved. So if the clipping did not change we can bail out early because it will not cause any observable difference anyway.
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=46976 Signed-off-by: Jan Kl��tzke jan@kloetzke.net