that doesn't have it. This is achieved by having minimal do-nothing stubs
enabled when there are no bpfilter devices configured.
Driver modules should be built with BPF enabled for maximum
convenience (but can be built without it for maximum performance).
XXX It probably makes sense to have a flag for bsd.kern.mk to avoid these
rules.
XXX IO_NDELAY seems to be the main reason for it, when used in a cdevsw
read or write "flag" context. Perhaps a redundant declaration
somewhere like sys/conf.h might help remove the need for vnode.h in
these device drivers in the first place.
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
