* cpppch.c (struct cpp_savedstate): Add defs and n_defs members.
	(count_defs): Keep track of number of defs as well as total size.
	(write_defs): Put every definition in cpp_savedstate's defs array.
	(comp_hashnode): Define.  Comparison function for qsort.
	(cpp_write_pch_deps): Sort definitions before writing them.
	(struct ht_node_list): Define. Like cpp_savedstate but simpler.
	(collect_ht_nodes): Define.
	(cpp_valid_state): When verifying that undefined identifiers in
	the pch file are still undefined, read a sorted list of undefined
	identifiers, collect all defined identifiers into a sorted list,
	and walk through both lists to make sure there's no match.

From-SVN: r65101