Fixed: Button state in "expired" state after busy mode

For instance, when using the mouse button to select menu
items, the Attack control wouldn't do anything until after
pressing and releasing the mouse button once.

doomsday/engine/portable/src/con_busy.c

@@ -450,6 +450,7 @@ static void Con_BusyLoop(void)
 
         // Post and discard all input events.
         DD_ProcessEvents(0);
+        DD_ProcessSharpEvents(0);
 
         Sys_Sleep(20);