Apply by doing:
       cd /usr/src
       patch -p0 < 015_kerntime.patch
And then rebuild your kernel.

Index: sys/kern/kern_time.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_time.c,v
retrieving revision 1.29
retrieving revision 1.29.2.1
diff -u -r1.29 -r1.29.2.1
--- sys/kern/kern_time.c        14 Mar 2002 01:27:04 -0000      1.29
+++ sys/kern/kern_time.c        2 Oct 2002 20:27:29 -0000       1.29.2.1
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kern_time.c,v 1.29 2002/03/14 01:27:04 millert Exp $  */
+/*     $OpenBSD: kern_time.c,v 1.29.2.1 2002/10/02 20:27:29 jason Exp $        */
/*     $NetBSD: kern_time.c,v 1.20 1996/02/18 11:57:06 fvdl Exp $      */

/*
@@ -426,13 +426,13 @@
       register_t *retval;
{
       register struct sys_getitimer_args /* {
-               syscallarg(u_int) which;
+               syscallarg(int) which;
               syscallarg(struct itimerval *) itv;
       } */ *uap = v;
       struct itimerval aitv;
       int s;

-       if (SCARG(uap, which) > ITIMER_PROF)
+       if (SCARG(uap, which) < ITIMER_REAL || SCARG(uap, which) > ITIMER_PROF)
               return (EINVAL);
       s = splclock();
       if (SCARG(uap, which) == ITIMER_REAL) {
@@ -465,7 +465,7 @@
       register_t *retval;
{
       register struct sys_setitimer_args /* {
-               syscallarg(u_int) which;
+               syscallarg(int) which;
               syscallarg(struct itimerval *) itv;
               syscallarg(struct itimerval *) oitv;
       } */ *uap = v;
@@ -474,7 +474,7 @@
       int s, error;
       int timo;

-       if (SCARG(uap, which) > ITIMER_PROF)
+       if (SCARG(uap, which) < ITIMER_REAL || SCARG(uap, which) > ITIMER_PROF)
               return (EINVAL);
       itvp = SCARG(uap, itv);
       if (itvp && (error = copyin((void *)itvp, (void *)&aitv,