These new facet functions were added to GCC 5.1 but the versions for the
old std::string ABI were never exported from the shared library.

	PR libstdc++/88681
	* config/abi/pre/gnu.ver: Add missing exports.
	* testsuite/22_locale/collate_byname/88681.cc: New test.
	* testsuite/22_locale/time_get/get/char/88681.cc: New test.
	* testsuite/22_locale/time_get/get/wchar_t/88681.cc: New test.

From-SVN: r267563