more environment problems; limit resource exhaustion; fix incorrect

more environment problems; limit resource exhaustion; fix incorrect
name in Connection timed out message; ANSI C fixes; log message sender on
returned mail during queue run; count recipients properly; fix YP code;
diagnose "message timed out" properly

SCCS-vsn: usr.sbin/sendmail/src/headers.c 6.5
SCCS-vsn: usr.sbin/sendmail/src/usersmtp.c 6.3
SCCS-vsn: usr.sbin/sendmail/src/recipient.c 6.3
SCCS-vsn: usr.sbin/sendmail/src/main.c 6.9
SCCS-vsn: usr.sbin/sendmail/src/conf.h 6.4
SCCS-vsn: usr.sbin/sendmail/src/arpadate.c 6.3
SCCS-vsn: usr.sbin/sendmail/src/err.c 6.2
SCCS-vsn: usr.sbin/sendmail/src/collect.c 6.3
SCCS-vsn: usr.sbin/sendmail/src/version.c 6.12
SCCS-vsn: usr.sbin/sendmail/src/savemail.c 6.3
SCCS-vsn: usr.sbin/sendmail/src/srvrsmtp.c 6.3
SCCS-vsn: usr.sbin/sendmail/src/util.c 6.4
SCCS-vsn: usr.sbin/sendmail/src/deliver.c 6.10
SCCS-vsn: usr.sbin/sendmail/src/queue.c 6.5
SCCS-vsn: usr.sbin/sendmail/src/conf.c 6.10
SCCS-vsn: usr.sbin/sendmail/src/map.c 6.2
SCCS-vsn: usr.sbin/sendmail/src/Makefiles/Makefile.dist 6.3