>diff -u -r1.41 kern_time.c
>--- kern_time.c        1999/10/10 18:41:53     1.41
>+++ kern_time.c        1999/11/08 15:48:44
>@@ -423,16 +423,17 @@
>       struct itimerval aitv;
>       int s;
>
>-      if ((u_int)which > ITIMER_PROF)
>+      if ((u_int)which > ITIMER_THREADV)
>               return (EINVAL);

Would it be a good idea at this point to introduce ITIMER_MAX,
_NITIMER or whatever the accepted name is, and test against that.
Then this bit of code won't need to be updated again next time.

Of course you still need to introduce new code to handle the new
timer, to the gain is marginal at best :-)

--sjg