Unbreak build on -stable while keep it buildable on -current.

Noticed by: quite a lot of people.

net/ngrep/Makefile

@@ -8,7 +8,7 @@
 
 PORTNAME=	ngrep
 PORTVERSION=	1.40.1
-PORTREVISION=	1
+PORTREVISION=	2
 CATEGORIES=	net security
 MASTER_SITES=	${MASTER_SITE_SOURCEFORGE}
 MASTER_SITE_SUBDIR=	${PORTNAME}
@@ -24,6 +24,12 @@ MAN8=		ngrep.8
 
 PORTDOCS=	BUGS CHANGES README README.pcre USAGE
 
+.include <bsd.port.pre.mk>
+
+.if ${OSVERSION} > 500000
+EXTRA_PATCHES=	${PATCHDIR}/patch5-configure ${PATCHDIR}/patch5-ngrep
+.endif
+
 post-install:
 .if !defined(NOPORTDOCS)
 	@${MKDIR} ${DOCSDIR}
@@ -32,4 +38,4 @@ post-install:
 .endfor
 .endif
 
-.include <bsd.port.mk>
+.include <bsd.port.post.mk>