Restrict system to x86_64-linux and x86_64-darwin

flake.nix

@@ -8,25 +8,25 @@
       flake = false;
     };
   };
-
-  outputs = { self, nixpkgs, utils, ... }:
-    utils.lib.eachDefaultSystem (system:
+  outputs = { self, nixpkgs, utils, flake-compat }:
+    utils.lib.eachSystem (with utils.lib.system; [ x86_64-linux aarch64-linux x86_64-darwin ]) (system:
       with import nixpkgs { inherit system; }; rec {
-        zkeme80 = runCommand "zkeme80.rom" { buildInputs = [ guile ]; } ''
+        packages = rec {
+          default = self.packages.${system}.runit;
+          zkeme80 = runCommand "zkeme80.rom" { buildInputs = [ guile ]; } ''
             cp -r ${./.}/src/* .
             chmod -R +w .
             echo '(begin (load "zkeme80.scm") (make-rom "zkeme80.rom"))' | guile
             mkdir $out
             cp zkeme80.rom $out/
           '';
-        defaultPackage = writeScript "runit" ''
+          runit = writeScript "runit" ''
             #!/usr/bin/env sh
             ${tilem}/bin/tilem2 -r ${zkeme80}/zkeme80.rom
           '';
-        defaultApp = {
-          type = "app";
-          program = "${defaultPackage}";
         };
+        defaultPackage = self.packages.${system}.default;
       }
     );
+
 }