misplaced extern declarations (mostly prototypes of interrupt handlers)
that this exposed. The prototypes should be moved back to the driver
sources when the functions are staticalized.
Added idempotency guards to <machine/conf.h>. "ioconf.h" can't be
included when building LKMs so define a wart in bsd.kmod.mk to help
guard against including it.
to <machine/conf.h>. conf.h was mechanically generated by
`grep ^d_ conf.c >conf.h'. This accounts for part of its ugliness. The
prototypes should be moved back to the driver sources when the functions
are staticalized.