Hi,

The following diff does roughly the following:

- eliminate opt_ktrace.h includes and ifdef KTRACE from most of the kernel
- provide stubs that can be called and do nothing if there is no ktrace
- don't require exposing proc/lwp or ktrace guts to ktrace feeders
- don't pass lwp_t * into each ktrace op

The main motivators for doing this are:

- eliminate a lot of ifdefs
- make it viable for LKMs to use/feed ktrace
- don't break ABI compatibility if struct proc/lwp or ktrace change

There's a global flag that's tested (ktrace_on) before any function calls
are made. In the common case (tracing off) it should be marginally cheaper.

	http://www.netbsd.org/~ad/ktrace.diff

Comments?

Thanks,
Andrew