anchor.diff:  , name ? "source"
   , ... } @ args:
   
  -lib.overrideDerivation (fetchurl ({
  +(fetchurl ({
     inherit name;
   
     recursiveHash = true;
  
positive.code: 
    postFetch =
      ''
        export PATH=${unzip}/bin:$PATH
  
        unpackDir="$TMPDIR/unpack"
        mkdir "$unpackDir"
        cd "$unpackDir"
  
negative.code:       mv "$unpackDir" "$out"
      '') #*/
      + extraPostFetch;
  } // removeAttrs args [ "stripRoot" "extraPostFetch" ])).overrideAttrs (x: {
    # Hackety-hack: we actually need unzip hooks, too
    nativeBuildInputs = x.nativeBuildInputs ++ [ unzip ];
  })
  