diff --git a/update_version b/update_version
new file mode 100755
index 0000000..a999991
--- /dev/null
+++ b/update_version
@@ -0,0 +1,65 @@
+#!/bin/bash
+
+# Creates and updates the package_version information used by configure.ac
+# (or other makefiles).  When run inside a git repository it will use the
+# version information that can be queried from it unless AUTO_UPDATE is set
+# to 'no'.  If no version is currently known it will be set to 'unknown'.
+#
+# If called with the argument 'release', the PACKAGE_VERSION will be updated
+# even if AUTO_UPDATE=no, but the value of AUTO_UPDATE shall be preserved.
+# This is used to force a version update whenever `make dist` is run.
+#
+# The exit status is 1 if package_version is not modified, else 0 is returned.
+#
+# This script should NOT be included in distributed tarballs, because if a
+# parent directory contains a git repository we do not want to accidentally
+# retrieve the version information from it instead.  Tarballs should ship
+# with only the package_version file.
+#
+# Ron <ron@debian.org>, 2012.
+
+SRCDIR=$(dirname $0)
+
+if [ -e "$SRCDIR/package_version" ]; then
+    . "$SRCDIR/package_version"
+fi
+
+if [ "$AUTO_UPDATE" = no ]; then
+    [ "$1" = release ] || exit 1
+else
+    AUTO_UPDATE=yes
+fi
+
+# We run `git status` before describe here to ensure that we don't get a false
+# -dirty from files that have been touched but are not actually altered in the
+# working dir.
+GIT_VERSION=$(cd "$SRCDIR" && git status > /dev/null 2>&1 \
+                           && git describe --tags --match 'v*' --dirty 2> /dev/null)
+GIT_VERSION=${GIT_VERSION#v}
+
+if [ -n "$GIT_VERSION" ]; then
+
+    [ "$GIT_VERSION" != "$PACKAGE_VERSION" ] || exit 1
+    PACKAGE_VERSION="$GIT_VERSION"
+
+elif [ -z "$PACKAGE_VERSION" ]; then
+    # No current package_version and no git ...
+    # We really shouldn't ever get here, because this script should only be
+    # included in the git repository, and should usually be export-ignored.
+    PACKAGE_VERSION="unknown"
+else
+    exit 1
+fi
+
+cat > "$SRCDIR/package_version" <<-EOF
+	# Automatically generated by update_version.
+	# This file may be sourced into a shell script or makefile.
+
+	# Set this to 'no' if you do not wish the version information
+	# to be checked and updated for every build.  Most people will
+	# never want to change this, it is an option for developers
+	# making frequent changes that they know will not be released.
+	AUTO_UPDATE=$AUTO_UPDATE
+
+	PACKAGE_VERSION="$PACKAGE_VERSION"
+EOF