Comment 13 for bug 1728132

I think we need to unblock this in the short term while work happens on 5.7; so I've built PXC packages using gcc-5:

 https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/3060

and gcc-6 for testing purposes:

 https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/3061

If gcc-6 built binaries prove stable, I'd propose we force pxc builds for 5.6 to using gcc-6 (which is trivial todo); I checked with doko and both 5 & 6 binaries will remain in archive (albeit 5 will be in universe) for bionic so we can 'fix' things this way.