re PR libstdc++/60497 (unique_ptr<T> tries to complete its type T even though it's not required to be a complete type)

	PR libstdc++/60497
	* include/std/tuple (get, __tuple_compare): Qualify more calls to
	prevent ADL. Cast comparison results to bool.
	* testsuite/20_util/tuple/60497.cc: Test accessing rvalues.
	* testsuite/20_util/tuple/comparison_operators/overloaded.cc: New.

From-SVN: r210366