mouse input lag under X11

[allebot]

Originally reported by: benoit-pierre

Original Ticket: alleg/bugs/396

When using a high polling rate mouse on Linux with X11, the mouse cursor lags under Adventure Game Studio. This is due to the fact that Allegro will only process up-to 5 X11 events at a time, and so mouse motion events will pile up and the mouse cursor will lag.

The attached patch remove this limitation of only processing 5 events or less at a time.

Assuming this patch is OK, this should probably be incorporated.

Patch does not appear correct? XPeekEvent is used to skip an event, then on the next loop iteration that keypress is processed again? Maybe I'm wrong but it looks like this adds extra KeyPress events.