anchor.diff:    # Return the complete set of packages, after applying the overrides
     # returned by the `overrider' function (see above).  Warning: this
     # function is very expensive!
  -  applyGlobalOverrides = overrider:
  +  pkgsWithOverrides = overrider:
       let
         overrides = super: overrider pkgs super // stdenvOverrides super;
   
  
positive.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 ./../..) {
  
negative.code:   # (un-overriden) set of packages, allowing packageOverrides
    # attributes to refer to the original attributes (e.g. "foo =
    # ... pkgs.foo ...").
    pkgs = pkgsWithOverrides (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
  