small fixes, nixpkgs-fmt

flake.nix

@@ -1,15 +1,21 @@
 {
   inputs = {
     nixpkgs-unstable.url = github:NixOS/nixpkgs/nixos-unstable;
+
     nixpkgs.url = github:NixOS/nixpkgs/nixos-22.05;
+
+    flake-utils.url = github:numtide/flake-utils;
+
     sops-nix = {
       url = github:Mic92/sops-nix;
       inputs.nixpkgs.follows = "nixpkgs";
     };
+
     microvm = {
       url = github:astro/microvm.nix;
       inputs.nixpkgs.follows = "nixpkgs";
     };
+
     fenix = {
       url = github:nix-community/fenix;
       inputs.nixpkgs.follows = "nixpkgs-unstable";
@@ -20,15 +26,31 @@
     inputs@{ self
     , nixpkgs
     , nixpkgs-unstable
+    , flake-utils
     , sops-nix
     , microvm
     , fenix
     , ...
     }:
+
+    flake-utils.lib.eachDefaultSystem
+      (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        packages.slick = pkgs.callPackage "${self}/pkgs/slick.nix" { };
+      })
+    //
     {
+      overlays.default = final: prev: {
+        inherit (self.packages.${prev.system})
+          slick;
+      };
       nixosConfigurations = {
         microwave = nixpkgs-unstable.lib.nixosSystem {
           system = "x86_64-linux";
+          specialArgs = { inherit inputs; };
           modules = [
             sops-nix.nixosModules.sops
             ./hosts/microwave
@@ -43,7 +65,10 @@
             ./modules/tlp.nix
             ./modules/virtualization.nix
             ({ pkgs, ... }: {
-              nixpkgs.overlays = [ fenix.overlay ];
+              nixpkgs.overlays = [
+                fenix.overlay
+                self.overlays.default
+              ];
               environment.systemPackages = with pkgs; [
                 (fenix.packages."x86_64-linux".stable.withComponents [
                   "cargo"