This allows the gnome-system-monitor to run.
It causes continous log spam and the network monitor doesn't work, but it doesn't crash on startup anymore.
Bring OpenBSD closer to FreeBSD to help checking what is missing/different.
Also we make sure to use and build mountlist and fsusage from the
sysdeps/openbsd directory instead of the common one.
https://bugzilla.gnome.org/show_bug.cgi?id=723521