PR libstdc++/69703
* src/c++11/codecvt.cc (__codecvt_utf8_base<char16_t>::do_in)):
Override endianness bit in mode.
* testsuite/22_locale/codecvt/codecvt_utf8/69703.cc: New test.
* testsuite/22_locale/codecvt/codecvt_utf8_utf16/66855.cc: Test
that little_endian mode is ignored.
* testsuite/experimental/filesystem/path/native/string.cc: New test.
From-SVN: r235216
