Move input event list initialisation and storage from DDX to DIX.

Rather than letting the DDX allocate the events, allocate them once in the DIX
and just pass it around when needed.

DDX should call GetEventList() to obtain this list and then pass it into
Get{Pointer|Keyboard}Events.

dix/getevents.c

@@ -70,6 +70,17 @@ extern Bool XkbCopyKeymap(XkbDescPtr src, XkbDescPtr dst, Bool sendNotifies);
 /* Number of motion history events to store. */
 #define MOTION_HISTORY_SIZE 256
 
+/* InputEventList is the container list for all input events generated by the
+ * DDX. The DDX is expected to call GetEventList() and then pass the list into
+ * Get{Pointer|Keyboard}Events.
+ */
+EventListPtr InputEventList = NULL;
+
+_X_EXPORT EventListPtr
+GetEventList()
+{
+    return InputEventList;
+}
 
 /**
  * Pick some arbitrary size for Xi motion history.