Major change: Redirect events instead of handle the notifies.

By specifying XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT, the window manager
will get map request events instead of map notify events, and therefore
can act sooner (the window won’t be positioned on the screen and moved
afterwards).

Furthermore, this fixes some problems with GIMP/VLC (and probably others)
which caused endless loops.

Also, events which should be ignored are now saved in a queue rather than
saving just the last event. This should eliminate race conditions.

Note that there is a new FIXME in src/handlers.c. Some windows generate
unmap notify events when reparenting while others don’t. We need to
understand, document and implement a more correct way to handle this.

include/handlers.h

@@ -15,8 +15,11 @@ int handle_key_release(void *ignored, xcb_connection_t *conn, xcb_key_release_ev
 int handle_key_press(void *ignored, xcb_connection_t *conn, xcb_key_press_event_t *event);
 int handle_enter_notify(void *ignored, xcb_connection_t *conn, xcb_enter_notify_event_t *event);
 int handle_button_press(void *ignored, xcb_connection_t *conn, xcb_button_press_event_t *event);
-int handle_map_notify_event(void *prophs, xcb_connection_t *conn, xcb_map_notify_event_t *event);
+int handle_map_request(void *prophs, xcb_connection_t *conn, xcb_map_request_event_t *event);
 int handle_configure_event(void *prophs, xcb_connection_t *conn, xcb_configure_notify_event_t *event);
+int handle_configure_request(void *prophs, xcb_connection_t *conn, xcb_configure_request_event_t *event);
+int handle_destroy_notify_event(void *data, xcb_connection_t *conn, xcb_destroy_notify_event_t *event);
+int handle_unmap_notify_event(void *data, xcb_connection_t *conn, xcb_unmap_notify_event_t *event);
 int handle_windowname_change(void *data, xcb_connection_t *conn, uint8_t state,
                                 xcb_window_t window, xcb_atom_t atom, xcb_get_property_reply_t *prop);
 int handle_expose_event(void *data, xcb_connection_t *conn, xcb_expose_event_t *event);