winex11: Retrieve raw mouse events through XInput2 while the cursor is clipped.

[Vitaliy Margolen]

It's great to see so much progress in this area! Great gob so far. However
this isn't enough.

Cursor doesn't have to be clipped to receive mouse event's. As far as
dinput goes, it will read mouse events regardless where the pointer is if
device is acquired in background mode. Or this isn't the final commit yet?

Vitaliy.