windows.dlfcn: set update script

pkgs/os-specific/windows/dlfcn/default.nix

@@ -3,6 +3,7 @@
   lib,
   fetchFromGitHub,
   cmake,
+  nix-update-script,
 }:
 
 stdenv.mkDerivation rec {
@@ -18,6 +19,8 @@ stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ cmake ];
 
+  passthru.updateScript = nix-update-script { };
+
   meta = {
     homepage = "https://github.com/dlfcn-win32/dlfcn-win32";
     description = "Set of functions that allows runtime dynamic library loading";