anchor.diff:    #
     # The result is `pkgs' where all the derivations depending on `foo'
     # will use the new version.
  -  overridePackages = f: lib.fix' (lib.extends f pkgs.__unfix__);
  +  overridePackages = f:
  +    let
  +      newpkgs = pkgsFun newpkgs overrides;
  +      overrides = mkOverrides pkgs (f newpkgs pkgs);
  +    in newpkgs;
   
     # Override system. This is useful to build i686 packages on x86_64-linux.
     forceSystem = system: kernel: (import ./all-packages.nix) {
  
positive.code: 
  
    ### Helper functions.
    inherit lib config;
  
    inherit (lib) lowPrio hiPrio appendToName makeOverridable;
    inherit (misc) versionedDerivation;
  
negative.code:     allPackages = args: import ./all-packages.nix ({ inherit config system; } // args);
    };
  
    defaultStdenv = allStdenvs.stdenv // { inherit platform; };
  
    stdenvCross = lowPrio (makeStdenvCross defaultStdenv crossSystem binutilsCross gccCrossStageFinal);
  
  