(my_strftime):

(my_strftime):
Define to nstrftime if emacs, but only if my_strftime is not defined.
(extra_args, extra_args_spec, extra_args_spec_iso): Rename from
ut_argument, ut_argument_spec, ut_argument_spec_iso, respectively.
Add one more extra argument: a nanoseconds value.
All uses changed.
(ns): New macro.
(my_strftime function): Add %N format.
(emacs_strftimeu): Renamed from emacs_strftime,
with extra ut argument.