Python 3.6 enabled: https://gitweb.gentoo.org/repo/gentoo.git/commit/app-portage?id=9845156c143c6d1ece2ae3a21da8a41daa6c3649 but revdep-rebuild needs the fix: https://gitweb.gentoo.org/proj/gentoolkit.git/commit/?id=d3ef9ef1bebc7604db0e8c5c49e167e18300c9e9 bug 617498. Also there is existing python 3.6 bug 616934.
I am also hitting this now
*** This bug has been marked as a duplicate of bug 617498 ***