title: How "...android.googlesource.../external/icu/" used by android studio & ndk?
body: <p>as the title, i try all my efforts to find out how to use it, but failed. there isn't any manual/readme to guide.
  obsolutely, I'm a rookie.
  can any one give some advices?
  <a href="https://android.googlesource.com/platform/external/icu/+/refs/heads/master" rel="nofollow noreferrer">android.googlesource.../external/icu/ address</a></p>