The translations module in master does not build against Python 3, however in many systems /usr/bin/python now is linked to the python 3 binary. The build was successful after relinking /usr/bin/python to the python 2 binary, so it's just a matter of updating the code. Attached is the building failure log.
Created attachment 51845 [details] transaltions module build failure log
Reproduced. I'll try to came up with a patch that works with both python2 and python3.
Should be fixed with http://cgit.freedesktop.org/libreoffice/core/commit/?id=d92a87f19534105ee9c29ba5e509fd99c31c3611