concept prove patch for ktrace output to all file types

This is a concept prove patch for ktrace. In order to make ktrace write to
stdout, /dev/xxx, fifo file, pipe, I changed ktrace syscall to accepting a
file handler instead of a file name.

I just get a workable kernel patch. And i make as small as possible changes
to userland code. Now you can do something like:
#mkfifo foo
in session A: #kdump -f foo
in session B: #ktrace -f foo ls

Then, you can see a real time output like truss did.

Before moving forward (hacking userland), i want to get some feedback if my
changes in kernel part is the right direction to do. Appreciate your time.

PS: The patch can be clearly apply to today's current.

-- 
-Howard