* include/bits/uses_allocator.h (__uses_allocator_construct): Qualify
	std::forward and ::new. Cast pointer to void*.
	* include/std/variant (_Variant_storage, _Union, _Variant_base)
	(__access, __visit_invoke, variant, visit): Qualify std::forward.
	* testsuite/20_util/variant/compile.cc: Test for ADL problems.

From-SVN: r240344