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:     removeAttrs alias ["recurseForDerivations"]
    else alias;
  
  in lib.mapAttrs tweakAlias aliases // pkgsRet;
  # end pkgsFun
  
  in pkgsFinal
  
negative.code:       AppKit Carbon Cocoa IOKit OSAKit Quartz QuartzCore WebKit
        ImageCaptureCore GSS ImageIO;
    });
    emacs24Macport = self.emacs24Macport_24_5;
  
    emacs25pre = lowPrio (callPackage ../applications/editors/emacs-25 {
      # use override to enable additional features
  