tree.h (TYPE_REF_IS_RVALUE): Define.

	* tree.h (TYPE_REF_IS_RVALUE): Define.
	* dwarf2out.c (attr_checksum_ordered, is_type_die, is_comdat_die,
	should_move_die_to_comdat, prune_unused_types_walk): Handle
	DW_TAG_rvalue_reference_type like DW_TAG_reference_type.
	(modified_type_die, gen_reference_type_die): Emit
	DW_TAG_rvalue_reference_type instead of DW_TAG_reference_type
	if TYPE_REF_IS_RVALUE and -gdwarf-4.

	* cp-tree.h (TYPE_REF_IS_RVALUE): Remove.

	* g++.dg/debug/dwarf2/rv1.C: New test.

From-SVN: r158542