How to include <sys/bus.h> without "device_if.h" and "bus_if.h"?

[Lev Serebryakov]

Hello, Freebsd-hackers.

  I need to include <sys/bus.h> in my kernel module to use
devctl_notify(). But my module doesn't have device_if.h or bus_if.h,
which are required by <sys/bus.h>.
  What should I do?

-- 
// Black Lion AKA Lev Serebryakov <lev at FreeBSD.org>