dwarf2out.c (struct die_struct): Document that die_sib makes a circular linked list.

dwarf2out.c (struct die_struct): Document that die_sib makes a circular linked list.

	* dwarf2out.c (struct die_struct): Document that die_sib makes
	a circular linked list.
	(FOR_EACH_CHILD): New.
	(reverse_die_lists): Delete.
	(reverse_all_dies): Delete.
	(add_dwarf_attr): Correct documentation.
	(remove_child_with_prev): New.
	(remove_child_TAG): Update for change to die_struct, use
	remove_child_with_prev.
	(add_child_die): Update for change to die_struct.
	(splice_child_die): Use remove_child_with_prev and add_child_die.
	(print_die): Use FOR_EACH_CHILD.
	(die_checksum): Likewise.
	(assign_symbol_names): Likewise.
	(output_location_lists): Likewise.
	(build_abbrev_table): Likewise.
	(calc_die_sizes): Likewise.
	(mark_dies): Likewise.
	(unmark_dies): Likewise.
	(unmark_all_dies): Likewise.
	(output_die): Likewise.
	(prune_unused_types_mark): Likewise.
	(prune_unused_types_walk): Likewise.
	(same_die_p): Update for change to die_struct.
	(break_out_includes): Likewise.
	(prune_unused_types_prune): Likewise.
	(add_sibling_attributes): Use FOR_EACH_CHILD, simplify logic.
	(prune_unmark_dies): Use FOR_EACH_CHILD, don't clear die_mark if
	it's already clear.
	(dwarf2out_finish): Don't call reverse_all_dies.

From-SVN: r113171