* doc/xml/manual/status_cxx2017.xml: Update status tables.
	* doc/html/manual/*: Regenerate.
	* include/std/type_traits (bool_constant): Define.
	* testsuite/20_util/bool_constant/requirements.cc: New.
	* testsuite/20_util/declval/requirements/1_neg.cc: Adjust dg-error.
	* testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc:
	Likewise.
	* testsuite/20_util/make_signed/requirements/typedefs_neg.cc:
	Likewise.

From-SVN: r224160