add smfh as a package for stable users

default.nix

@@ -193,6 +193,7 @@ in
             after = [ "arbys-prep.service" ];
             script =
               let
+                linker = lib.getExe (pkgs.smfh or pkgs.rustPlatform.buildRustPackage ./smfh.nix { });
               in
               ''
                 new_manifest=${manifest}