+/* If we're displaying frames using a window system that can stack
+ frames on top of each other, this hook allows you to bring a frame
+ to the front, or bury it behind all the other windows. If this
+ hook is zero, that means the device we're displaying on doesn't
+ support overlapping frames, so there's no need to raise or lower
+ anything.
+
+ If RAISE is non-zero, F is brought to the front, before all other
+ windows. If RAISE is zero, F is sent to the back, behind all other
+ windows. */
+void (*frame_raise_lower_hook) ( /* FRAME_PTR f, int raise */ );
+