* include/bits/alloc_traits.h (__allow_copy_cons): Remove.
	(__check_copy_constructible): Likewise.
	* include/bits/unordered_map.h (unordered_map, unordered_multimap):
	Do not derive from __check_copy_constructible.
	* include/bits/unordered_set.h (unordered_set, unordered_multiset):
	Likewise.
	* testsuite/23_containers/unordered_map/55043.cc: It is no longer
	necessary for is_copy_constructible to be correct to use nested
	unordered containers.
	* testsuite/23_containers/unordered_multimap/55043.cc: Likewise.
	* testsuite/23_containers/unordered_set/55043.cc: Likewise.
	* testsuite/23_containers/unordered_multiset/55043.cc: Likewise.

From-SVN: r204790