gtk-doc is not needed (#444564 by Laszlo Szalma)

(Portage version: 2.2.10/cvs/Linux x86_64, signed Manifest commit with key A188FBD4)
fix file collision with systemd

(Portage version: 2.2.10/cvs/Linux x86_64, signed Manifest commit with key BDEED020)
Add new revision for ruby21.

(Portage version: 2.2.8-r1/cvs/Linux x86_64, signed Manifest commit with key 0x8883FA56A308A8D7!)