PR libstdc++/85040
	* include/bits/stl_function.h (greater::__not_overloaded)
	(less::__not_overloaded, greater_equal::__not_overloaded)
	(less_equal::__not_overloaded): Fix ambiguous specializations.
	* testsuite/20_util/function_objects/comparisons_pointer.cc: Add
	tests for type with overlaoded operators.

From-SVN: r258773