initial nix flake rewrite

flake.nix

@@ -2,6 +2,9 @@
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
     wfvm.url = "git+https://git.m-labs.hk/m-labs/wfvm";
+
+    # wfvm uses a very old branch of nixpkgs (2023-05-25)
+    wfvm.inputs.nixpkgs.follows = "nixpkgs";
   };
 
   outputs =
@@ -11,15 +14,15 @@
       wfvm,
     }:
     let
-      pkgs = import nixpkgs;
+      # import nixpkgs
+      pkgs = (import nixpkgs {});
     in
     {
-      packages."x86_64-linux".windows-vm = wfvm.lib.makeWindowsImage {
-        # configuration parameters go here
-        windowsImage = pkgs.requireFile {
-          name = "Tiny11_24H2_English_x64.iso";
+      packages."${pkgs.system}".windows-vm = wfvm.lib.makeWindowsImage {
+        windowsImage = (pkgs.fetchurl {
+          url = "file:///home/primary/Downloads/tiny11.iso";
           sha256 = "ea9cee512457c763484dbeaeee98caba8c2e69e0420bdae8c4508e31ad8ccd99";
-        };
+        });
 
         installCommands = [
           {