* dwarf2out.c (die_struct): Remove die_attr_last and die_child_last.
        (add_dwarf_attr, add_child_die): Just push onto the front.
        (reverse_die_lists): New fn.
        (add_sibling_attributes): Use it.
        (push_decl_scope): Reorganize.
        (gen_struct_or_union_type_die): Don't add a DW_AT_containing_type
        that points to ourself.
        (add_name_and_src_coords_attributes): Don't set file and line for
        an artificial decl.
        (gen_subprogram_die): An artificial function doesn't need to match
        file and line.
        (gen_compile_unit_die): Return the generated die.  Only add
        AT_comp_dir if the filename is relative.
        (remove_AT): Simplify loop.  Also free string values.
        (output_die): A DIE ref can't be null.
        (output_value_format, value_format): Take a dw_attr_ref.
        (dwarf_last_decl, is_extern_subr_die, sibling_offset): Remove.
        (AT_class, AT_flag, AT_int, AT_unsigned, AT_string, AT_ref, AT_loc,
        AT_addr, AT_lbl): New fns.
        (various): Use them.
        (various): Constify.

From-SVN: r30624