Flake simplification

flake.nix

@@ -11,7 +11,6 @@
 
   outputs = { self, nixpkgs, dhall-haskell, genode-depot }:
     let
-      nixpkgs' = import nixpkgs;
       systems = [ "x86_64-genode" ];
 
       forAllSystems = f: nixpkgs.lib.genAttrs systems (system: f system);
@@ -22,8 +21,7 @@
 
       packages = forAllSystems (system:
         import ./packages.nix {
-          inherit system;
-          nixpkgs = nixpkgs';
+          inherit system nixpkgs;
         });
 
       checks = forAllSystems (system:

packages.nix

@@ -2,17 +2,17 @@
 #
 # SPDX-License-Identifier: LicenseRef-Hippocratic-1.1
 
-{ system ? "x86_64-genode", nixpkgs ? import <nixpkgs>, extraOverlays ? [ ] }:
+{ system, nixpkgs }:
 
 let
   toolchainOverlay = import ./toolchain-overlay;
   # Overlay of toolchain patches
 
-  super = nixpkgs {
+  super = import nixpkgs {
     # Evaluate an overlayed Nixpkgs for a Genode target
     localSystem = "x86_64-linux";
     crossSystem = "x86_64-genode";
-    overlays = [ toolchainOverlay ] ++ extraOverlays;
+    overlays = [ toolchainOverlay ];
   };
 
   inherit (super) callPackage;