re PR libstdc++/45549 (merge is_iterator into iterator_traits)

re PR libstdc++/45549 (merge is_iterator into iterator_traits)

2010-09-07  Paolo Carlini  <paolo.carlini@oracle.com>
	    Marc Glisse  <marc.glisse@normalesup.org>

	PR libstdc++/45549
	* include/bits/cpp_type_traits.h (__is_iterator_helper): Rename to
	__has_iterator_category.
	(__is_iterator): Adjust.
	* include/bits/stl_iterator_base_types.h (__iterator_traits): Add
	in C++0x mode, use the latter.
	(iterator_traits): In C++0x mode, derive from the latter.
	* include/bits/stl_iterator_base_funcs.h (next, prev): Remove
	enable_if on the return type.

Co-Authored-By: Marc Glisse <marc.glisse@normalesup.org>
From-SVN: r163977