For proper PolicyKit usage, add the following lines to rc.local(8):
if [ -x "${PREFIX}/bin/polkit-auth ]; then
	install -d -m 0770 -g _polkituser /var/run/PolicyKit
fi

PolicyKit needs access to the process namespace using procfs. To do so,
it needs a process file system. Just `mkdir /proc' and add the following
lines to your fstab(5):
/proc /proc procfs ro 0 0
