dev-python/sympy-1.0[doc] fails to emerge without app-text/docbook2X
build.log?
Created attachment 429158 [details] build.log
commit c25aadf4d684872f411ad8e9db89184099c794ac Author: Andrey Grozin <grozin@gentoo.org> Date: Mon Mar 28 18:53:02 2016 +0600 dev-python/sympy: with USE=doc now depends on app-text/docbook2X Bug: 577966 Package-Manager: portage-2.2.28