clan: Re-add pkgsForSystem to configsPerSystem too

lib/build-clan/module.nix

@@ -105,12 +105,7 @@ let
           name: _:
           nixosConfiguration {
             inherit name system;
-
-            # We removed pkgsForSystems because we have the problem that nixpkgs.* options are then ignored
-            # However our current model is to have the hardware config read and then set nixpkgs.hostPlatform automatically
-            # which gets ignored if we set pkgsForSystems. pkgsForSystems also needed to be set as else 
-            # pkgs was equals to null in nixosConfiguration above which broke something else
-            pkgs = nixpkgs.legacyPackages.${system};
+            pkgs = pkgsForSystem system;
           }
         ) allMachines
       )