as possible. For that, split out a function which does the allocation
of a softc (without linking it into global structures) and a function
which inserts the device into the global alldevs lists and the per-driver
cd_devs.
There is a little semantic change involved: the pseudo-device code didn't
interpret FSTATE_STAR as such, for no good reason. This looks harmless;
I'll modify driver frontends as I find ways to test.
Get config_makeroom() out of the public namespace - that's clearly an
internal of autoconf which drivers can't be allowed to deal with.