add mkNteDerivation helper function

flake.nix

@@ -13,8 +13,9 @@
     functions = forEachSystem (
       system: let
         pkgs = pkgsForEach.${system};
-      in {
+      in rec {
         engine = import ./engine.nix pkgs;
+        mkNteDerivation = import ./nte-drv.nix pkgs engine;
       }
     );
 

nte-drv.nix

@@ -0,0 +1,18 @@
+pkgs: engine: {
+  name,
+  version,
+  src,
+  extraArgs ? {},
+  entries ? [],
+  templates ? [],
+}: pkgs.stdenv.mkDerivation {
+  inherit name version src;
+
+  buildPhase = /*sh*/''
+    runHook preBuild
+
+    ${engine src {inherit extraArgs entries templates;}}
+
+    runHook postBuild
+  '';
+}