and the "kernel.tar.Z" distribution on louie.udel.edu, which is older than
xntp 3.4y or 3.5a, but contains newer kernel source fragments.
This commit adds support for a new kernel configuration option, NTP.
If NTP is selected, then the system clock should be run at "HZ", which
must be defined at compile time to be one value from:
60, 64, 100, 128, 256, 512, 1024.
Powers of 2 are ideal; 60 and 100 are supported but are marginally less
accurate.
If NTP is not configured, there should be no change in behavior relative
to pre-NTP kernels.
These changes have been tested extensively with xntpd 3.4y on a decstation;
almost identical kernel mods work on an i386. No pulse-per-second (PPS)
line discipline support is included, due to unavailability of hardware
to test it.
With this in-kernel PLL support for NetBSD, both xntp 3.4y and xntp
3.5a user-level code need minor changes. xntp's prototype for
syscall() is correct for FreeBSD, but not for NetBSD.
jonathan