--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/build-aux/mk-hg-id.sh	Fri Jun 24 14:46:04 2016 -0400
@@ -0,0 +1,58 @@
+#! /bin/sh
+#
+# Copyright (C) 2016 John W. Eaton
+#
+# This file is part of Octave.
+#
+# Octave 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 of the License, or (at
+# your option) any later version.
+#
+# Octave 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 Octave; see the file COPYING.  If not, see
+# <http://www.gnu.org/licenses/>.
+
+# Generate a header file that provides the public symbols from Octave's
+# autoconf-generated config.h file.  See the notes at the top of the
+# generated octave-config.h file for more details.
+
+set -e
+
+if [ $# -ne 1 ] && [ $# -ne 2 ]; then
+  echo "usage: mk-hg-id.sh SRCDIR [--disable]" 1>&2
+  exit 1
+fi
+
+srcdir="$1"
+
+hg_id=HG-ID
+move_if_change="$srcdir/build-aux/move-if-change"
+
+if [ $# -eq 2 ] && [ x"$2" = x--disable ]; then
+  echo "hg-id-disabled" > ${hg_id}-t
+  ${move_if_change} ${hg_id}-t ${hg_id}
+elif [ -d $srcdir/.hg ]; then
+  ( cd $srcdir && hg identify --id || echo "unknown" ) > ${hg_id}-t
+  ${move_if_change} ${hg_id}-t ${hg_id}
+elif [ ! -f $srcdir/${hg_id} ]; then
+  echo "WARNING: $srcdir/HG-ID is missing!" 1>&2
+  echo "unknown" > ${hg_id}-t && mv ${hg_id}-t ${hg_id}
+else
+  echo "preserving existing HG-ID file" 1>&2
+  if [ "x$srcdir" != "x." ] && [ -f $srcdir/${hg_id} ] && [ ! -f ${hg_id} ]; then
+    cp ${srcdir}/${hg_id} ${hg_id}
+    touch -r ${srcdir}/${hg_id} ${hg_id}
+  fi
+fi
+
+if [ "`cat ${hg_id}`" = "hg-id-disabled" ]; then
+  echo "WARNING: HG-ID is 'hg-id-disabled'" 1>&2
+fi
+
+cat ${hg_id}