rem: (void*) userdata;
add: (void) userdata;
context: bool glgfx_viewport_haschanged(struct glgfx_viewport* viewport) {  bool has_changed = viewport->has_changed;  viewport->has_changed = false;  void check(gpointer* data, gpointer* userdata) {    struct glgfx_rasinfo* rasinfo = (struct glgfx_rasinfo*) data;    (void*) userdata;    if (glgfx_bitmap_haschanged(rasinfo->bitmap) || rasinfo->has_changed) {      has_changed = true;    }    rasinfo->has_changed = false;  }  // Always call glgfx_bitmap_haschanged, since we want to reset its  // has_changed flag.  g_list_foreach(viewport->rasinfos, (GFunc) check, viewport);  return has_changed;}