PR libstdc++/64657
	* include/bits/basic_string (basic_string::_S_copy_chars): Cast
	expression to void.
	* include/bits/locale_facets_nonio.tcc (money_get::_M_extract,
	time_get::_M_extract_num, time_get::_M_extract_name,
	time_get::_M_extract_wday_or_month): Likewise.
	* include/bits/stl_algo.h (__includes, __replace_copy_if,
	__is_sorted_until, __is_permutation, transform): Likewise.
	* include/bits/stl_algobase.h (swap_ranges, __copy_move::__copy_m,
	__equal::equal, __lexicographical_compare_impl, equal): Likewise.
	* include/bits/stl_numeric.h (inner_product): Likewise.
	* include/bits/stl_uninitialized.h (__uninitialized_copy_a): Likewise.
	* testsuite/util/testsuite_iterators.h (output_iterator_wrapper,
	input_iterator_wrapper): Declare unusable comma operator.
	* testsuite/21_strings/basic_string/cons/char/64657.cc: New.
	* testsuite/21_strings/basic_string/modifiers/assign/char/64657.cc:
	New.

From-SVN: r222579