MFC the xlocale implementation.
Merged revisions: 227487,227753,227807,227818,227999,228002,228875,230156,231673,232498,232601,232620,232626,232926-232927,232929,232931,232935,233173,233600,234573,234578,235239
This currently defines __NO_TLS on ARM (unlike head), because the required
support function has not been MFC'd.