flake: packages: convert to 'flake-parts'

flake/default.nix

@@ -26,8 +26,6 @@ let
       default = self.apps.${system}.diff-flake;
     };
 
-    packages = import ./packages.nix inputs system;
-
     # Work-around for https://github.com/nix-community/home-manager/issues/3075
     legacyPackages = {
       homeConfigurations = {
@@ -75,6 +73,7 @@ flake-parts.lib.mkFlake { inherit inputs; } {
     ./lib.nix
     ./nixos.nix
     ./overlays.nix
+    ./packages.nix
   ];
 
   flake = (eachMySystem systemDependant);

flake/packages.nix

@@ -1,10 +1,13 @@
-{ self, futils, nixpkgs, ... }:
-system:
-let
-  inherit (futils.lib) filterPackages flattenTree;
-  pkgs = nixpkgs.legacyPackages.${system};
+{ self, inputs, ... }:
+{
+  perSystem = { pkgs, system, ... }: {
+    packages =
+      let
+        inherit (inputs.futils.lib) filterPackages flattenTree;
         packages = import "${self}/pkgs" { inherit pkgs; };
         flattenedPackages = flattenTree packages;
         finalPackages = filterPackages system flattenedPackages;
-in
-finalPackages
+      in
+      finalPackages;
+  };
+}