Merge from gnulib

This incorporates:
2017-05-01 New module 'localtime-buffer'
2017-04-30 utimens: Add support for native Windows
* admin/merge-gnulib (AVOIDED_MODULES): Add tzset.
* configure.ac (tzset): No need for Emacs itself to check now.
* lib/gettimeofday.c, lib/time.in.h, lib/time_rz.c, lib/utimens.c:
* m4/gettimeofday.m4, m4/time_h.m4, m4/time_rz.m4: Copy from gnulib.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib/localtime-buffer.c, lib/localtime-buffer.h:
* m4/localtime-buffer.m4: New files, copied from gnulib.
* src/editfns.c (init_editfns): Assume tzset is callable.

1 files changed, 58 insertions, 0 deletions

diff --git a/lib/localtime-buffer.c b/lib/localtime-buffer.c
new file mode 100644
index 00000000000..f84ad3e8238
--- /dev/null
+++ b/lib/localtime-buffer.c
@@ -0,0 +1,58 @@
+/* Provide access to the last buffer returned by localtime() or gmtime().
+
+   Copyright (C) 2001-2003, 2005-2007, 2009-2017 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
+
+/* written by Jim Meyering */
+
+#include <config.h>
+
+/* Specification.  */
+#include "localtime-buffer.h"
+
+#if GETTIMEOFDAY_CLOBBERS_LOCALTIME || TZSET_CLOBBERS_LOCALTIME
+
+static struct tm tm_zero_buffer;
+struct tm *localtime_buffer_addr = &tm_zero_buffer;
+
+/* This is a wrapper for localtime.
+
+   On the first call, record the address of the static buffer that
+   localtime uses for its result.  */
+
+struct tm *
+rpl_localtime (time_t const *timep)
+{
+  struct tm *tm = localtime (timep);
+
+  if (localtime_buffer_addr == &tm_zero_buffer)
+    localtime_buffer_addr = tm;
+
+  return tm;
+}
+
+/* Same as above, since gmtime and localtime use the same buffer.  */
+struct tm *
+rpl_gmtime (time_t const *timep)
+{
+  struct tm *tm = gmtime (timep);
+
+  if (localtime_buffer_addr == &tm_zero_buffer)
+    localtime_buffer_addr = tm;
+
+  return tm;
+}
+
+#endif