--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/mk-hg-id.sh	Wed Jan 03 14:18:12 2018 +0100
@@ -0,0 +1,45 @@
+#! /bin/sh
+#
+# Copyright (C) 2016-2018 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 file that holds the hg id of the mxe-octave source tree.
+
+# set -e
+
+if [ $# -ne 1 ]; then
+  echo "usage: mk-hg-id.sh SRCDIR" 1>&2
+  exit 1
+fi
+
+srcdir="$1"
+
+hg_id=HG-ID
+
+if [ -d $srcdir/.hg ]; then
+  ( cd $srcdir && hg identify --id || echo "unknown" ) > ${hg_id}-t && mv ${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}
+  fi
+fi
+