anchor.diff:        renamed="$TMPDIR/${baseNameOf url}"
         mv "$downloadedFile" "$renamed"
         unpackFile "$renamed"
  -
  -      shopt -s dotglob
       ''
       + (if stripRoot then ''
         if [ $(ls "$unpackDir" | wc -l) != 1 ]; then
  
positive.code:       fi
        fn=$(cd "$unpackDir" && echo *)
        if [ -f "$unpackDir/$fn" ]; then
          mv "$unpackDir/$fn" "$out"
        else
          mv "$unpackDir/$fn"/* "$out/"
        fi
      '' else ''
        mv "$unpackDir"/* "$out/"
      '') #*/
      + extraPostFetch;
  } // removeAttrs args [ "stripRoot" "extraPostFetch" ]))
  
negative.code:   postFetch =
      ''
        export PATH=${unzip}/bin:$PATH
  
        unpackDir="$TMPDIR/unpack"
        mkdir "$unpackDir"
  