drop flake-utils

Using these few lines of polyfill should help avoid end user's
flake.lock being polluted with sometimes hard to deduplicate
dependencies (i.e., ghostty)

flake.nix

@@ -3,7 +3,6 @@
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.11";
-    flake-utils.url = "github:numtide/flake-utils";
 
     # Used for shell.nix
     flake-compat = {
@@ -15,11 +14,22 @@
   outputs = {
     self,
     nixpkgs,
-    flake-utils,
     ...
   }: let
+    inherit (nixpkgs) lib;
+
+    # flake-utils polyfill
+    eachSystem = systems: fn:
+      lib.foldl' (
+        acc: system:
+          lib.recursiveUpdate
+          acc
+          (lib.mapAttrs (_: value: {${system} = value;}) (fn system))
+      ) {}
+      systems;
+
     systems = ["x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin"];
-    outputs = flake-utils.lib.eachSystem systems (system: let
+    outputs = eachSystem systems (system: let
       pkgs = nixpkgs.legacyPackages.${system};
     in rec {
       # The packages exported by the Flake:
@@ -33,7 +43,10 @@
       # this will use the latest default.
       apps = rec {
         default = apps.zig;
-        zig = flake-utils.lib.mkApp {drv = packages.default;};
+        zig = {
+          type = "app";
+          program = toString packages.default;
+        };
       };
 
       # nix fmt