Change nl_langinfo to nl_langinfo_l using locale given as argument.
Remove outdated TRANSITION_PERIOD_HACK. The codeset is stored in
the locale for quite some time now. For !MB_CAPABLE targets, just
return "US_ASCII" as codeset.
Implement nl_langinfo by calling nl_langinfo_l. Export nl_langinfo_l
from Cygwin DLL and bump minor API version number.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>