New comment by ifreund on void-packages repository

https://github.com/void-linux/void-packages/pull/24580#issuecomment-683934947

Comment:
> I believe the build is trying to use scdoc from the target, not the host. Should look into how that's being done.

Added a fix for this to the patch, will submit it upstream in a minute as well. 

Also changed the service to pass `-g seatd` and added an install message.