* lib/strptime.h (strptime): Use 'restrict' for args where

* lib/strptime.h (strptime): Use 'restrict' for args where
POSIX requires this.
* lib/strptime.c (strptime): Likewise.
Change license notice from LGPL to GPL, since gnulib-tool will
change this as needed.
Include <config.h> if _LIBC is not defined, not if HAVE_CONFIG_H is
defined.
Include "strptime.h" first, to check interface.
Do not #undef _LIBC and _NL_CURRENT.
Do not include <stdlib.h>; no longer needed.
Include "time_r.h" and declare ptime_locale_status
only if _LIBC is not defined.
(__P): Remove unused macro.
(match_string): Bring back glibc version, but use it only if _LIBC
is defined.
(__strptime_internal): Compile tm_gmtoff code if _LIBC is defined, too.
Remove unnecessary assertion and abort() call.
Use #ifdef _NL_CURRENT rather than #if 0, for benefit of glibc.
* m4/strptime.m4: Fix serial number comment.
(gl_FUNC_STRPTIME): Require AC_C_RESTRICT, gl_TM_GMTOFF.
* modules/strptime (Files): Add m4/tm_gmtoff.m4.
(Depends-on): Add time_r.