The v3 version was heavily adapted and it does work nice in cross compile environments already. Are you sure there is a benefit of updating it?
The benefit of frequently updating to new versions of foreign code is that when you don't, you will have a really hard time updating later when you _do_ want some new feature. If you do update, you also get bug fixes for bugs that you do not (yet!) run into yourself, etc. It saves a lot of work. Frequent back-merges are easy, trying to do one after a few years can often be almost impossible.
If you don't keep track of foreign code, you'll find yourself maintaining a fork of that foreign code, at which point it might have been better to just write the whole code from scratch.
Segher