better logic

modules/platform/mkhost.nix

@@ -1,9 +1,9 @@
 { inputs, ... }: {
-  flake.lib.mkHost = { system ? "x86_64-linux", user, extraModules ? [] }:
+  flake.lib.mkHost = { system, user, host, extraModules ? [] }:
     inputs.nixpkgs.lib.nixosSystem {
       inherit system;
       specialArgs = {
-        inherit user;
+        inherit user host;
         pkgs-unstable = import inputs.nixpkgs-unstable {
           inherit system;
           config.allowUnfree = true;