It seems this script was broken because of the SYSINIT changes and a
rather awkward variable initialisation. For some reason the
make_device_driver.sh script is also broken, related to BUS_SETUP_INTR.
I have no experience with FreeBSD's interrupt handling, so I hope
someone else is willing to take a look at that shell script.
PR: misc/126435
MFC after: 1 month