Simplify flake

flake.lock

@@ -39,7 +39,23 @@
     "root": {
       "inputs": {
         "naersk": "naersk",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "utils": "utils"
+      }
+    },
+    "utils": {
+      "locked": {
+        "lastModified": 1637014545,
+        "narHash": "sha256-26IZAc5yzlD9FlDT54io1oqG/bBoyka+FJk5guaX4x4=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "bba5dcc8e0b20ab664967ad83d24d64cb64ec4f4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
       }
     }
   },

flake.nix

@@ -3,76 +3,24 @@
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    utils.url = "github:numtide/flake-utils";
     naersk.url = "github:nmattia/naersk";
     naersk.inputs.nixpkgs.follows = "nixpkgs";
   };
 
-  outputs = { self, nixpkgs, naersk }:
+  outputs = { self, nixpkgs, utils, naersk }:
     let
       cargoToml = (builtins.fromTOML (builtins.readFile ./Cargo.toml));
-      supportedSystems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" ];
-      forAllSystems = f: nixpkgs.lib.genAttrs supportedSystems (system: f system);
     in
-    {
-      overlay = final: prev: {
-        "${cargoToml.package.name}" = final.callPackage ./. { inherit naersk; };
+    utils.lib.eachDefaultSystem (system: let
+      pkgs = nixpkgs.legacyPackages."${system}";
+      naersk-lib = naersk.lib."${system}";
+    in rec {
+      packages."${cargoToml.package.name}" = naersk-lib.buildPackage {
+        pname = "${cargoToml.package.name}";
+        root = ./.;
+        buildInputs = [ pkgs.openssl ];
       };
-
-      packages = forAllSystems (system:
-        let
-          pkgs = import nixpkgs {
-            inherit system;
-            overlays = [
-              self.overlay
-            ];
-          };
-        in
-        {
-          "${cargoToml.package.name}" = pkgs."${cargoToml.package.name}";
-        });
-
-
-      defaultPackage = forAllSystems (system: (import nixpkgs {
-        inherit system;
-        overlays = [ self.overlay ];
-      })."${cargoToml.package.name}");
-
-      checks = forAllSystems (system:
-        let
-          pkgs = import nixpkgs {
-            inherit system;
-            overlays = [
-              self.overlay
-            ];
-          };
-        in
-        {
-          format = pkgs.runCommand "check-format"
-            {
-              buildInputs = with pkgs; [ rustfmt cargo ];
-            } ''
-            ${pkgs.rustfmt}/bin/cargo-fmt fmt --manifest-path ${./.}/Cargo.toml -- --check
-            ${pkgs.nixpkgs-fmt}/bin/nixpkgs-fmt --check ${./.}
-            touch $out # it worked!
-          '';
-          "${cargoToml.package.name}" = pkgs."${cargoToml.package.name}";
-        });
-      devShell = forAllSystems (system:
-        let
-          pkgs = import nixpkgs {
-            inherit system;
-            overlays = [ self.overlay ];
-          };
-        in
-        pkgs.mkShell {
-          inputsFrom = with pkgs; [
-            pkgs."${cargoToml.package.name}"
-          ];
-          buildInputs = with pkgs; [
-            rustfmt
-            nixpkgs-fmt
-          ];
-          LIBCLANG_PATH = "${pkgs.llvmPackages.libclang.lib}/lib";
-        });
-    };
-}
+      defaultPackage = packages."${cargoToml.package.name}";
+    });
+}