* include/bits/uses_allocator.h (uses_allocator_v): New.
	* include/std/functional (is_bind_expression_v, is_placeholder_v):
	Likewise.
	* testsuite/20_util/bind/is_placeholder_v.cc: Likewise.
	* testsuite/20_util/declval/requirements/1_neg.cc: Adjust.
	* testsuite/20_util/duration/literals/range.cc: Likewise.
	* testsuite/20_util/duration/requirements/typedefs_neg1.cc: Likewise.
	* testsuite/20_util/duration/requirements/typedefs_neg2.cc: Likewise.
	* testsuite/20_util/duration/requirements/typedefs_neg3.cc: Likewise.
	* testsuite/20_util/make_signed/requirements/typedefs_neg.cc: Likewise.
	* testsuite/20_util/make_unsigned/requirements/typedefs_neg.cc:
	Likewise.
	* testsuite/20_util/ratio/operations/ops_overflow_neg.cc: Likewise.
	* testsuite/20_util/uses_allocator/requirements/uses_allocator_v.cc:
	New.

From-SVN: r238921