ADD: support for heinzelwerk CI/CD chain

.buildbot/undist/01-unpack.sh

@@ -0,0 +1,23 @@
+if test -z "$DIST_FORMAT" ; then
+	DIST_FORMAT="gztar"
+fi
+
+if test -z "$DIST_FILE" ; then
+	echo "Environment variable DIST_FILE must not be empty" >&2
+	exit 1
+fi
+
+if test -n "$INSTALL_DIR" ; then
+	mkdir -p "$INSTALL_DIR"
+	set -- --strip-components=1 -C "$INSTALL_DIR"
+fi
+
+case "$DIST_FORMAT" in
+gztar)
+	tar -xzf "$DIST_FILE" $*
+	;;
+*)
+	echo "Unsupported DIST_FORMAT ($DIST_FORMAT)" >&2
+	exit 1
+	;;
+esac