2005-01-23  Elijah Newren  <newren@gmail.com>

	Restore original stacking when aborting an alt-esc window switch
	operation.  Fixes #123576.

	* src/display.c: (GRAB_OP_IS_WINDOW_SWITCH): new macro,
	(meta_display_close): clear grab_old_window_stacking if non-NULL,
	(event_callback): restore stack positions if alt-esc op cancelled
	with button press, (meta_display_begin_grab_op): store the old
	stacking positions, (meta_display_end_grab_op): free the old stack
	positions

	* src/display.h: (struct _MetaDisplay): add a
	grab_old_window_stacking list

	* src/keybindings.c: (process_tab_grab): restore stack positions
	if alt-esc op cancelled with an errant key press

	* src/stack.c: (compare_just_window_stack_position): new
	GCompareFunc function, (meta_stack_get_positions): get current
	stack positions, (compare_pointers): new GCompareFunc function,
	(lists_contain_same_windows): simple utility func to see if two
	lists contains the same windows, (meta_stack_set_positions): new
	function to set the positions of all the windows in the stack

	* src/stack.h: (meta_stack_get_postions,
	meta_stack_set_positions): new functions