* dwarf2out.c (free_AT): Delete.
	(remove_AT): Update string ref counts.
	(remove_child_TAG): Don't call free_die.
	(free_die): Delete.
	(break_out_includes): Don't call free_die on DW_TAG_GNU_BINCL
	or DW_TAG_GNU_EINCL.
	(prune_unused_types_walk_attribs): Reset string refcounts.
	(prune_unused_types_update_strings): New.
	(prune_unused_types_prune): Don't make unnecessary stores.  Don't
	call free_die.  Do call prune_unused_types_update_strings.
	(prune_unused_types): Empty debug_str_hash.

From-SVN: r113012