I found a subroutine in printjob.c called sendmail with uses _PATH_SENDMAIL.
I found it all over the place:
blue src # ack _PATH_SENDMAIL
include/paths.h
63:#define _PATH_SENDMAIL "/usr/sbin/sendmail"
usr.bin/calendar/io.c
410: execl(_PATH_SENDMAIL, "sendmail", "-i", "-t", "-F",
412: warn(_PATH_SENDMAIL);
usr.bin/mail/send.c
422: cp = _PATH_SENDMAIL;
usr.bin/rdist/docmd.c
137: _PATH_SENDMAIL);
140: error("notify: \"%s\" failed\n", _PATH_SENDMAIL);
usr.bin/sendbug/sendbug.c
339: execl(_PATH_SENDMAIL, "sendmail",
usr.bin/skeyaudit/skeyaudit.c
215: execl(_PATH_SENDMAIL, "sendmail", "-t", (char *)NULL);
216: warn("cannot run \"%s -t\"", _PATH_SENDMAIL);
usr.bin/vacation/vacation.c
475: execl(_PATH_SENDMAIL, "sendmail", "-f", myname, "--",
477: syslog(LOG_ERR, "can't exec %s: %m", _PATH_SENDMAIL);
usr.bin/vi/common/recover.c
826: if (_PATH_SENDMAIL[0] != '/' || stat(_PATH_SENDMAIL, &sb))
828: _PATH_SENDMAIL, "not sending email: %s");
838: "%s -t < %s", _PATH_SENDMAIL, fname);
usr.sbin/cron/config.h
40:#define MAILARG _PATH_SENDMAIL /*-*/
usr.sbin/lpr/lpd/printjob.c
1079: if ((cp = strrchr(_PATH_SENDMAIL, '/')) != NULL)
1082: cp = _PATH_SENDMAIL;
1083: execl(_PATH_SENDMAIL, cp, "-t", (char *)NULL);
Chris
