arch-tools ebuild rdepends on app-portage/gentoolkit-dev, since that was moved to gentoolkit-0.4, we would need to allow that package version to also satisfy the dep Thanks :)
Meantime, maybe python 3.5/3.6 support could be added too ;)
You are the only user of arch-tools in my overlay :D I fixed it without testing the ebuild. If you have issues please let me know.
https://gitweb.gentoo.org/dev/ago.git/commit/?id=54e9f306583b9fb6cca4934248451160cb585234