Import the NetBSD rdate command and remove the Minix rdate command.
The default behaviour for both is the same. The NetBSD version adds
options to just display the time, adjust the time using adjtime(),
and set the time without printing the time.
Porting Notes:
- Compiles cleanly out of the box without any warnings
- Path changes from /usr/bin/rdate to /usr/sbin/rdate
- checked pkgsrc for any usages of rdate (none found)
- checked src for any usages of rdate (none found)
Testing:
- all command line options work (tested with time.nist.gov server)
- Native and cross build OK