gallium: Don't forget to get overllaping blits working again.

src/gallium/auxiliary/util/u_blit.c

@@ -311,6 +311,7 @@ util_blit_pixels(struct blit_state *ctx,
    assert(screen->is_format_supported(screen, dst->format, PIPE_TEXTURE));
 
    if(dst->format == src->format && (dstX1 - dstX0) == srcW && (dstY1 - dstY0) == srcH) {
+      /* FIXME: this will most surely fail for overlapping rectangles */
       pipe->surface_copy(pipe, FALSE,
 			 dst, dstX0, dstY0,   /* dest */
 			 src, srcX0, srcY0, /* src */