Import base.nix by default

lib/system.nix

@@ -4,15 +4,19 @@
             let
                 lib = nixpkgs.lib;
                 configPath = ./machines/${name}.nix;
+                machineConfig =
+                    if builtins.pathExists configPath then
+                        configPath
+                    else
+                        ./hardware/base.nix;
             in
                 lib.nixosSystem {
                     system = "x86_64-linux";
                     modules = [
                         (
                             { config, pkgs, ... }: {
-                                imports = lib.concatLists [
+                                imports = [
-                                    (lib.optional (builtins.pathExists configPath) configPath)
+                                    machineConfig
-                                    []
                                 ];
                             })
                     ];