* include/std/functional (_Mem_fn_traits_base::__arity): New typedef.
	(_Mem_fn_base::_Arity): New typedef.
	(_Bind_check_arity): New class template.
	(_Bind_helper, _Bindres_helper, _Bind_simple_helper): Check arity.
	* testsuite/20_util/bind/ref_neg.cc: Adjust dg-error.

From-SVN: r217025