* ggc.h (ggc_push_context): Fix comment.
	(ggc_pop_context): Likewise.
	(mark_string_if_gcable): Likewise.
	* ggc-common.c (ggc_mark_rtx_children): Use
	ggc_mark_string_if_gcable.
	* ggc-page.c (ggc_lookup_page_table): New function.
	(ggc_allocated_p): Likewise.
	(mark_obj): Fix formatting.
	(ggc_mark_string_if_gcable): New function.
	* ggc-simple.c (ggc_allocated_strings): New variable.
	(ggc_strings_used): Likewise.
	(ggc_compare_addresses): New function.
	(ggc_pop_context): Pop the `any' memory too.
	(ggc_mark_string_if_gcable): New function.
	(ggc_collect): Initialize and tear down ggc_allocated_strings.

From-SVN: r29897