* cp-tree.h (DECL_DEFERRED_CONSTEXPR_CHECK): New.
	* semantics.c (validate_constexpr_fundecl): Set it.
	(check_deferred_constexpr_decls): Clear it.
	(register_constexpr_fundef): Make sure it isn't set.
	* decl.c (grok_special_member_properties): Check it.

From-SVN: r173707