* include/experimental/any: Add feature-testing macro.
	* include/experimental/optional: Likewise.
	* include/experimental/string_view: Likewise.
	* include/experimental/tuple: Likewise.
	* include/experimental/type_traits: Likewise.
	* testsuite/experimental/any/misc/any_cast_neg.cc: Adjust dg-error.

From-SVN: r216848