echangelog-tng appears to be a snapshot of an old echangelog script. It was originally included with overlay-utils because the echangelog it was a snapshot of didn't support SVN. echangelog-tng is now broken on things like git, whereas the official echangelog (From stable app-portage/gentoolkit-dev ) supports all sorts of repos (including mercurial :-D) quite well. Also, it should be a simple sed expression to fix sunrise-commit to call echangelog instead of echangelog-tng...
once you added the missing dependency on gentoolkit-dev and got it reviewed, feel free to not forget to close this bug ;-)
Ooops, here you go.