I managed to successfully build http://mentors.debian.net/debian/pool/main/c/capnproto/capnproto_0.5.2-1.dsc against experimental/GCC-5 using pbuilder.
Not sure if you're actively attempting test rebuilds every so often, but feel free to try for yourself when 0.5.2-1 hits unstable. -- *Tom Lee */ http://tomlee.co / @tglee <http://twitter.com/tglee>
