dev-util/systemtap-3.0 has been released 2016-03-28 old versions quickly become obsolete with kernel updates. Renaming ebuild works for me on linux-4.4.16. Reproducible: Always
Ebuild added to my overlay and modified to create the 3 groups needed for regular users to run stap: https://github.com/stefantalpalaru/gentoo-overlay/tree/master/dev-util/systemtap
The current release is 3.1, 2017-02-17
commit fa7388a25e1de7a9389d3676f8a6b9ddb6a385b6 Author: Lars Wendler <polynomial-c@gentoo.org> Date: Fri Feb 24 10:38:56 2017 +0100 dev-util/systemtap: Bump to version 3.1 Package-Manager: Portage-2.3.3, Repoman-2.3.1