* debug.c (struct debug_handle): Remove class_mark field. Add

	* debug.c (struct debug_handle): Remove class_mark field.  Add
	id_list and compare_list fields.
	(struct debug_class_id): Define.
	(struct debug_type_compare_list): Define.
	(debug_write): Initialize info->id_list
	(debug_write_name): Remove reference to info->class_mark.
	(debug_write_type): Get id for all structs and classes.  Simplify
	test for whether struct has already been written.
	(debug_write_class_type): Get id for all classes.  Simplify test
	for whether class has already been written.
	(debug_write_block): Don't write out blocks other than the top
	level block if they have no local variables.
	(debug_set_class_id): New static function.
	(debug_type_samep): New static function.
	(debug_class_type_samep): New static function.
	* prdbg.c (pr_start_struct_type): Always print id.
	(pr_start_class_type): Likewise.
	(pr_tag_type): Likewise.