Bug#778108: root-system: ftbfs with GCC-5

[peter green]

>
> the new upstream version fixes the build failures with GCC 5. Had to work around
> the build failure on armhf, and enabled the builds for powerpc and ppc64el.
> Note that I forgot to prepare the dfsg tarball.
>
> https://launchpad.net/ubuntu/+source/root-system/5.34.30-0ubuntu3
Note that there is now a ubuntu5 version which fixes at least one 
further build failure.