Program enhancements (2/3)

ftpd(8): 'advertize', 'maxfilesize', 'sanenames', -e emailaddr, -P dataport, -q/-Q (do/don't use pidfiles), -u/-U (do/don't log to utmp), -w/-W (do/don't log to wtmp), -X (syslog wu-ftpd style xferlogs)
ifconfig(8): -A (list up interfaces only) now the default
ktrace(1): -s (synchronized writes)
mbrlabel(8): don't modify disklabel unless requested