add E11SYNC_HTTP_PORT

flake.nix

@@ -86,10 +86,11 @@
           cp -r ${self}/app $out
           makeWrapper ${pkgs.python3Packages.gunicorn}/bin/gunicorn $out/bin/entrypoint \
             --chdir $out/app \
+            --set-default E11SYNC_HTTP_PORT ${toString gunicornPort} \
             --set E11SYNC_DEBUG "" \
             --set E11SYNC_COMPRESS_OFFLINE 1 \
             --set GEOIP_PATH "${geoip}" \
-            --add-flags --bind=127.0.0.1:${toString gunicornPort} \
+            --add-flags --bind=127.0.0.1:\$E11SYNC_HTTP_PORT \
             --add-flags e11sync.wsgi
         '';
         passthru.tests = {