allow limited 8-bit support; allow [TCP] as an alias for [IPC], even

allow limited 8-bit support; allow [TCP] as an alias for [IPC], even
though it's wrong; restore t option for System V support; add L=_N_
mailer option for line lengths; implement R mailer flag to get
restricted port; misc cleanup

SCCS-vsn: usr.sbin/sendmail/src/main.c 5.42
SCCS-vsn: usr.sbin/sendmail/src/conf.h 5.23
SCCS-vsn: usr.sbin/sendmail/src/collect.c 5.11
SCCS-vsn: usr.sbin/sendmail/src/version.c 5.90
SCCS-vsn: usr.sbin/sendmail/src/sendmail.h 5.28
SCCS-vsn: usr.sbin/sendmail/src/daemon.c 5.42
SCCS-vsn: usr.sbin/sendmail/src/util.c 5.23
SCCS-vsn: usr.sbin/sendmail/src/readcf.c 5.31
SCCS-vsn: usr.sbin/sendmail/src/deliver.c 5.52
SCCS-vsn: usr.sbin/sendmail/src/conf.c 5.33