I should have removed x11-libs/glamor at the same time as xorg-server-1.16 in bug 607096.
commit 2f0a85146427813ecf3317c691c59de17138735c Author: Matt Turner <mattst88@gentoo.org> Date: Sun Feb 26 16:23:34 2017 -0800 profiles: Mask x11-libs/glamor for removal.
Removed: commit 572046e7f4be1e31df4793c7609dcd778d165f97 Author: Matt Turner <mattst88@gentoo.org> Date: Wed Mar 29 08:08:11 2017 -0700 package.mask: Drop masks for removed x11-libs/glamor Bug: https://bugs.gentoo.org/611058 commit 05a9f2574ae4c11052fdeb2d4ec9ddd813de1b2b Author: Matt Turner <mattst88@gentoo.org> Date: Wed Mar 29 08:07:06 2017 -0700 x11-libs/glamor: Remove package Bug: https://bugs.gentoo.org/611058