Fix visual-bell on X
* src/pgtkterm.c (pgtk_flash): Change size source.
On X, surface_orig is not an image surface but xlib surface, so I
cannot get its size with cairo_image_surface_get_{width,height}.
* src/pgtkterm.c (pgtk_flash): Change size source.
On X, surface_orig is not an image surface but xlib surface, so I
cannot get its size with cairo_image_surface_get_{width,height}.