2010-10-05  Paolo Carlini  <paolo.carlini@oracle.com>

	* include/std/type_traits (_GLIBCXX_HAS_NESTED_TYPE): Add.
	* include/std/functional (_Has_result_type_helper,
	_Has_result_type): Remove; use the above to define __has_result_type.
	* include/bits/stl_iterator_base_types.h: Use the above to define
	__has_iterator_category.
	* include/bits/allocator.h (__has_allocator_type): Use the above.
	* include/bits/cpp_type_traits.h (__has_iterator_category,
	__is_iterator): Remove.