message: simpler command to perform directory link
diff: @@ -36,7 +36,7 @@ then
  then
  test -d jalson && rm -fr jalson
  mv jalson-${jalson_ver} jalson
  - ln -snf ../external jalson/external
  + (cd jalson && ln -snf ../external .)
  else
  echo failed to find the directory jalson-${jalson_ver}
  fi
  