integrate user SMTP into sendmail itself. If there is no $u arg

integrate user SMTP into sendmail itself.  If there is no $u arg
in the mailer argument list, SMTP is run.  This can be used directly
over the Ethernet or to any clever mailer.  We still need to edit
spooled control files to remove recipients that have been successfully
sent during queue processing.

SCCS-vsn: usr.sbin/sendmail/src/deliver.c 3.53
SCCS-vsn: usr.sbin/sendmail/src/savemail.c 3.23
SCCS-vsn: usr.sbin/sendmail/src/version.c 3.63
SCCS-vsn: usr.sbin/sendmail/src/usersmtp.c 3.4