Use flake-utils, use mkShell

This fixes the devshell on darwin

flake.lock

@@ -1,5 +1,23 @@
 {
   "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
     "gitignore": {
       "inputs": {
         "nixpkgs": [
@@ -38,9 +56,25 @@
     },
     "root": {
       "inputs": {
+        "flake-utils": "flake-utils",
         "gitignore": "gitignore",
         "nixpkgs": "nixpkgs"
       }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
     }
   },
   "root": "root",

flake.nix

@@ -3,16 +3,16 @@
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
     gitignore = {
       url = "github:hercules-ci/gitignore.nix";
       inputs.nixpkgs.follows = "nixpkgs";
     };
   };
 
-  outputs = { self, nixpkgs, gitignore }:
+  outputs = { self, nixpkgs, flake-utils, gitignore }: flake-utils.lib.eachDefaultSystem (system:
     let
-    system = "x86_64-linux";
+      pkgs = import nixpkgs { inherit system; };
-    pkgs = nixpkgs.legacyPackages.${system};
 
       vrnp-static = pkgs.buildGoModule {
         pname = "vrnp";
@@ -31,15 +31,15 @@
         CGO_ENABLED = 0;
       };
     in {
-    devShell.${system} = pkgs.mkShellNoCC {
+      devShell = pkgs.mkShell {
         packages = [
           pkgs.go
           (pkgs.python3.withPackages (ps: with ps; [ pillow ]))
         ];
       };
-    packages.${system} = {
+      packages = {
         default = vrnp-static;
-      image-meta = pkgs.runCommand "vrnp-version" {} ''
+        image-meta = pkgs.runCommand "image-meta" {} ''
           mkdir -p $out
           echo -n ${vrnp-static.version} > $out/version
           echo -n git.pbrinkmeier.de/paul/vrnp:${vrnp-static.version} > $out/name
@@ -55,5 +55,6 @@
           config.Cmd = [ "${vrnp-static}/bin/vrnp" ];
         };
       };
-  };
+    }
+  );
 }