2012-05-15  Paolo Carlini  <paolo.carlini@oracle.com>

	PR libstdc++/53339
	* include/bits/hashtable_policy.h (__detail::_Identity,
	__detail::_Select1st): Add.
	(_Map_base, _Hashtable_base): Use the latter, adjust parameters.
	* include/bits/hashtable.h (_Hashtable::__key_extract): Adjust.
	* include/bits/unordered_set.h (__uset_hashtable, __umset_hashtable):
	Likewise.
	* include/bits/unordered_map.h (__umap_hashtable, __ummap_hashtable):
	Likewise.
	* include/bits/stl_function.h (_Identity, _Select1st, _Select2nd)
	Unconditionally derive from unary_function.
	* include/ext/functional (identity, select1st, select2nd): Remove
	#ifdef __GXX_EXPERIMENTAL_CXX0X__ bits.
	* testsuite/23_containers/unordered_map/requirements/53339.cc: New.
	* testsuite/23_containers/unordered_multimap/requirements/
	53339.cc: Likewise.