enum34-1.1.3/setup.py does 'import setuptools' now. This has changed since 1.1.2 (and 1.0.4). Thanks!
commit b524284059f3a57778cec583d2d16b8a7a3455fd Author: Ian Delaney <idella4@gentoo.org> Date: Fri May 20 23:03:17 2016 +0800 dev-python/enum34: add setuptools to DEPEND in vn. 1.1.3 Noted by haubi in the gentoo bug, fixes the bug Gentoo-bug: #581366