See https://github.com/adrianopol/paq-overlay/blob/master/dev-python/zeroconf/zeroconf-0.17.2.ebuild.
This is already in Portage, as dev-python/zeroconf no less.
Evidently this package was added after this bug was created, but the developer was not aware of it at the time. commit 908fbf30751d39ab7f7f46280ef84e3473d50612 Author: Justin Lecher <jlec@gentoo.org> Date: Wed Feb 17 09:23:31 2016 +0100 dev-python/zeroconf: New package, ebuild written by me