Add OpenBSD Support

Anybody interested in getting ungoogled-chromium into the OpenBSD ports tree?

Same problem as with FreeBSD, they have up-to-date Chromium and Iridium, but ungoogled-chromium would make so much more sense!

On OpenBSD Chromium is made to make use of unveil:

If you run it with --enable-unveil, Chromium will be prevented (at the OS level) from accessing anything other than your ~/Downloads folder.

FYI I'm not using OpenBSD (yet) but I'm evaluating its use on my laptop. I'm not a developer and I'm not qualified to create and/or maintain a port, so this really is just a feature request in case someone else with the required skills and the same desire should be interested.