Import new gnulib.

m4/off_t.m4

@@ -0,0 +1,18 @@
+# off_t.m4 serial 1
+dnl Copyright (C) 2012-2013 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Check whether to override the 'off_t' type.
+dnl Set WINDOWS_64_BIT_OFF_T.
+
+AC_DEFUN([gl_TYPE_OFF_T],
+[
+  m4_ifdef([gl_LARGEFILE], [
+    AC_REQUIRE([gl_LARGEFILE])
+  ], [
+    WINDOWS_64_BIT_OFF_T=0
+  ])
+  AC_SUBST([WINDOWS_64_BIT_OFF_T])
+])