Don't add the atrun-line to the crontab when MK_AT is set.

This prevents spurious calls to sendmail every 5 minutes.

MFC after:	1 week

etc/Makefile

@@ -161,6 +161,9 @@ distribution:
 		${BIN2} ${DESTDIR}/etc; \
 	    ${INSTALL} -o ${BINOWN} -g ${BINGRP} -m 600 \
 		master.passwd nsmb.conf opieaccess ${DESTDIR}/etc;
+.if ${MK_AT} == "no"
+	sed -i "" -e '/atrun/d' ${DESTDIR}/etc/crontab
+.endif
 .if ${MK_TCSH} == "no"
 	sed -i "" -e 's;/bin/csh;/bin/sh;' ${DESTDIR}/etc/master.passwd
 .endif