Add a test script to check subsystem order as part of make check.

scripts/maint/run_check_subsystem_order.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+
+set -e
+
+TOR="${abs_top_builddir:-.}/src/app/tor"
+
+INCLUDES_PY="${abs_top_srcdir:-.}/scripts/maint/practracker/includes.py"
+
+if ! test -x "${INCLUDES_PY}" ; then
+    echo "skip"
+    exit 77
+fi
+
+"${TOR}" --dbg-dump-subsystem-list | \
+    "${INCLUDES_PY}" --check-subsystem-order -
+
+echo ok