* include/wchar.h: Declare __mbsrtowcs_l.
* wcsmbs/Makefile (routines): Add mbsrtowcs_l.
* wcsmbs/mbsrtowcs.c: Add support for compilation with
USE_IN_EXTENDED_LOCALE_MODEL.
* wcsmbs/mbsrtowcs_l: New file.
* wcsmbs/wcsmbsload.c (__wcsmbs_to_wc): Renamed from to_wc. Don't
define as static. Change all uses.
(__wcsmbs_getfct): Renamed from getfct. Don't define as static.
Change all callers.
* wcsmbs/wcsmbsload.h: Declare __wcsmbs_to_wc and __wcsmbs_getfct.
* time/strftime.c: When translating for the extended locale model
use the _l functions.
* time/Makefile (tests): Add tst-ftime_l.
* time/tst-ftime_l.c: New file.