I just copied the ebuild across, and it compiled and started, but I think I still suffer from Bug #128382 (which hit me on 2.14.4), only it actually starts this time, just with no gstreamer pipeline settings.
2.15.5.1 and 2.16.0 have also now been released (should I update the summary?)
2.16.1 is in the tree, marking this as fixed