recvmmsg(2) is buggy in 11.0-RELEASE, but not recent 11-STABLE or HEAD

-- the consequence for rsyslog being that it does not record any log
messages received via UDP to a log file.

recvmmsg(2) fix was applied to HEAD in r307036 and MFC'd to 11-STABLE
in r307311.  Therefore prevent configure testing for recvmmsg(2)
before OSVERSION 1100504.  Note: this is a no-op for older releases
than 11 -- recvmmsg(2) doesn't exist there.

PR:		214428
Reported by:	dch@skunkwerks.at
MFH:		2016Q4

sysutils/rsyslog8/Makefile

@@ -2,6 +2,7 @@
 
 PORTNAME=	rsyslog
 PORTVERSION=	8.22.0
+PORTREVISION=	1
 CATEGORIES=	sysutils
 MASTER_SITES=	http://www.rsyslog.com/files/download/rsyslog/
 
@@ -120,6 +121,9 @@ post-patch:
 	@${GREP} -rl '/etc/rsyslog.conf' ${WRKSRC}|${XARGS} ${REINPLACE_CMD} -e\
 		's|/etc/rsyslog.conf|${PREFIX}/etc/rsyslog.conf|'
 	@${REINPLACE_CMD} -e 's,/lib/rsyslog,${PREFIX}/lib/rsyslog,' ${WRKSRC}/tools/syslogd.c
+.if ${OPSYS} == FreeBSD && ${OSVERSION} < 1100504
+	@${REINPLACE_CMD} -e 's,recvmmsg ,,' ${WRKSRC}/configure.ac
+.endif
 	@${FIND} ${WRKSRC} -name '*.bak' -delete
 
 .include <bsd.port.post.mk>