20060511:
The machdep.* sysctls and the adjkerntz utility have been modified a bit. The new adjkerntz utility uses the new sysctl names and sysctlbyname() calls, so it may be impossible to run an old /sbin/adjkerntz utility in single-user mode with a new kernel. Replace the `adjkerntz -i' step before `make installworld' with:

/usr/obj/usr/src/sbin/adjkerntz/adjkerntz -i

and proceed as usual with the rest of the installworld-stage steps. Otherwise, you risk installing binaries with their timestamp set several hours in the future, especially if you are running with local time set to GMT+X hours.
$FreeBSD: src/UPDATING,v 1.449 2006/05/15 15:47:45 keramida Exp $