* src/c++11/codecvt.cc (write_utf16_code_point): Fix code to output
	surrogate pairs.
	(utf16_in): Pass mode argument to write_utf16_code_point.
	(codecvt<char16_t, char, mbstate_t>::do_in): Set mode according to
	native byte order.
	* testsuite/22_locale/codecvt/char16_t.cc: New.
	* testsuite/22_locale/codecvt/in/wchar_t/1.cc: Fix typo.

From-SVN: r220793