http://www.rsyslog.com/downloads/download-v8-stable/
Already in my overlay ready for the tree, waiting for polynomial-c or Ultrabug to pick up.
In tree since 2016-02-05: https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=b78301c462346539a72f29020eda566c3549be5f Thanks for reporting!