anchor.diff:    # (un-overriden) set of packages, allowing packageOverrides
     # attributes to refer to the original attributes (e.g. "foo =
     # ... pkgs.foo ...").
  -  pkgs = applyGlobalOverrides pkgsInit (self: config.packageOverrides or (super: {}));
  +  pkgs = applyGlobalOverrides (self: config.packageOverrides or (super: {}));
   
     # stdenvOverrides is used to avoid circular dependencies for building the
     # standard build environment. This mechanism use the override mechanism to
  
positive.code:     lib.optionalAttrs (crossSystem == null && pkgs.stdenv ? overrides)
        (pkgs.stdenv.overrides pkgs);
  
    # The un-overriden packages, passed to `overrider'.
    pkgsInit = pkgsFun pkgs;
  
    # Return the complete set of packages, after applying the overrides
    # returned by the `overrider' function (see above).  Warning: this
    # function is very expensive!
    applyGlobalOverrides = pkgsOrig: overrider:
      let
        overrides = overrider pkgs pkgsOrig // stdenvOverrides pkgsOrig;
  
        # The overriden, final packages.
        pkgs = pkgsFun pkgs // overrides;
  
negative.code:   #
    # The result is `pkgs' where all the derivations depending on `foo'
    # will use the new version.
    overridePackages = f: applyGlobalOverrides f;
  
    # Override system. This is useful to build i686 packages on x86_64-linux.
    forceSystem = system: kernel: (import ./../..) {
  