-# was originally from nls.m4 serial 1 (gettext-0.12)
-AC_DEFUN([AM_MKINSTALLDIRS],
+
+# AX_CHECK_MOUNT_OPT: an autoconf macro to check for generic filesystem-
+# agnostic 'mount' options. Written by Nicholas Clark. Looks for constants in
+# sys/mount.h to predict whether the 'mount' utility will support a specific
+# mounting option.
+#
+# This macro can be used to check for the presence of 'nodev' (or other mount
+# options), which isn't uniformly implemented in the BSD family at the time of
+# this writing. Tested on FreeBSD, NetBSD, OpenBSD, and Linux.
+#
+# Usage:
+#
+# AX_CHECK_MOUNT_OPT(option)
+#
+# Defines HAVE_MOUNT_$OPTION (in uppercase) if the option exists, and sets
+# ac_cv_mount_$option (in original case) otherwise.
+#
+# Copyright (c) 2018 Nicholas Clark <nicholas.clark@gmail.com>
+#
+# Copying and distribution of this file, with or without modification, are
+# permitted in any medium without royalty or attribution requirement.
+
+AC_DEFUN([AX_CHECK_MOUNT_OPT], [__AX_CHECK_MOUNT_OPT(m4_tolower([$1]),m4_toupper([$1]))])
+AC_DEFUN([__AX_CHECK_MOUNT_OPT],