Fix cast to rvalue reference from prvalue.

Fix cast to rvalue reference from prvalue.

	* cvt.c (diagnose_ref_binding): Handle rvalue reference.
	* rtti.c (build_dynamic_cast_1): Don't try to build a reference to
	non-class type.  Handle xvalue argument.
	* typeck.c (build_reinterpret_cast_1): Allow cast from prvalue to
	rvalue reference.
	* semantics.c (finish_compound_literal): Do direct-initialization,
	not cast, to initialize a reference.

From-SVN: r260622