* call.c (convert_class_to_reference): Binding an lvalue to an
	rvalue reference is bad.  If the user-defined conversion is bad,
	set bad_p before merging conversions.
	(maybe_handle_ref_bind): Don't push down bad_p.
	(reference_binding): Binding an lvalue to an rvalue reference is bad.
	(convert_like_real): Give a helpful error about binding lvalue
	to rvalue reference.
	(reference_related_p): No longer static.
	* typeck.c (build_typed_address): New.
	(build_static_cast_1): Add static_cast from lvalue to &&.
	* cp-tree.h: Adjust.

	* include/bits/move.h (forward): Implement as in N2835.
	(move): Implement as in N2831.
	* include/std/istream (rvalue stream operator>>): New.
	* include/std/ostream (rvalue stream operator<<): New.

Co-Authored-By: Douglas Gregor <doug.gregor@gmail.com>

From-SVN: r150327