On OpenBSD the backlight percentage cannot be retrieved in a simple way.
The only two solutions we are aware of for now are:
- reading from /dev/ttyC0: which isn't possible without changing
permissions or running slstatus as root
- linking against xcb-xrandr: which is bloat and does not work in every
case appearently
This reverts commit
37724ac2c3f496f4736223d0d8e5d8fecb933590 for now.