Add submodule alignment stub helper script

flake.nix

@@ -30,6 +30,16 @@
   outputs = { self, nixpkgs, linphone-sdk, ispell-src, ... }: {
 
     overlays.default = final: prev: {
+      
+      chore = {
+        update-from-submodules = prev.stdenv.mkDerivation rec {
+          name = "update-from-submodules";
+          src = ./tools/nix-align.sh;
+          unpackPhase = "true";
+          buildPhase = "true";
+          installPhase = "mkdir -p $out/bin; cp $src $out/bin/$name";
+        };
+      };
 
       linphone = prev.linphone.overrideAttrs (attrs:
         let overriddenSrc = linphone-sdk.nixUtils.overrideSource self; in

tools/nix-align.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+# Copyright (C) 2010-2023 Belledonne Communications SARL
+# SPDX-License-Identifier: AGPL-3.0-or-later
+#
+# Small helper script to align nix with submodules
+
+set -euxo pipefail
+
+git describe
+nix flake update
+nix build