More X optimizations

Now that bitmap_drv_request_some_pixels() just calls
bitmap_drv_request_pixels(), there's no point in calling expose_rect()
when ev->xexpose.count isn't zero.

src/conio/x_events.c

@@ -870,6 +870,7 @@ static int x11_event(XEvent *ev)
 			expose_rect(ev->xgraphicsexpose.x, ev->xgraphicsexpose.y, ev->xgraphicsexpose.width, ev->xgraphicsexpose.height);
 			break;
 		case Expose:
+			if (ev->xexpose.count == 0)
 				expose_rect(ev->xexpose.x, ev->xexpose.y, ev->xexpose.width, ev->xexpose.height);
 			break;