mi: switch the EQ to contain InternalEvents only.

This gets rid of the nevents parameter, InternalEvents are always a single
item per event. Also remove the special DeviceValuator handling in both
enqueueing and dequeueing.

Custom callback handlers are now broken until fixed.

For bisectability, we copy the InternalEvent back into the XI required during
POE and friends. Consider this a temporary solution.

Note: Because of misc linker bonghits, Xvfb won't link in this revision.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

include/input.h

@@ -108,7 +108,9 @@ typedef struct _EventList {
     int evlen; /* length of allocated memory for event in bytes.  This is not
                   the actual length of the event. The event's actual length is
                   32 for standard events or 32 +
-                  ((xGenericEvent*)event)->length * 4 for GenericEvents */
+                  ((xGenericEvent*)event)->length * 4 for GenericEvents.
+                  For events in the EQ, the length is
+                  ((InternalEvent*)event)->u.any.length */
 } EventList, *EventListPtr;
 
 /* The DIX stores incoming input events in this list */