From Paul Eggert.

lib/utimecmp.h

@@ -0,0 +1,38 @@
+/* utimecmp.h -- compare file time stamps
+
+   Copyright (C) 2004 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 2, 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, write to the Free Software Foundation,
+   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+
+/* Written by Paul Eggert.  */
+
+#ifndef UTIMECMP_H
+#define UTIMECMP_H 1
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+/* Options for utimecmp.  */
+enum
+{
+  /* Before comparing, truncate the source time stamp to the
+     resolution of the destination file system and to the resolution
+     of utimens.  */
+  UTIMECMP_TRUNCATE_SOURCE = 1
+};
+
+int utimecmp (char const *, struct stat const *, struct stat const *, int);
+
+#endif