gcc/ChangeLog:

2016-01-12  Trevor Saunders  <tbsaunde+gcc@tbsaunde.org>

	PR middle-end/54809
	* doc/gty.texi: Remove documentation of mark_hook.
	* gengtype.c (struct write_types_data): Remove code to support
	mark_hook attribute.
	(walk_type): Likewise.
	(write_func_for_structure): Likewise.

From-SVN: r232309