DR 488
	PR libstdc++/58357
	* include/bits/algorithmfwd.h (rotate): Return an iterator.
	* include/bits/stl_algo.h (rotate, __rotate): Likewise.
	* testsuite/25_algorithms/rotate/dr488.cc: New.
	* testsuite/25_algorithms/rotate/check_type.cc: Adjust function type.
	* testsuite/25_algorithms/rotate/requirements/explicit_instantiation/
	2.cc: Likewise.
	* testsuite/25_algorithms/rotate/requirements/explicit_instantiation/
	pod.cc: Likewise.

From-SVN: r219793