Index: head/net-mgmt/py3-dnsdiag/Makefile
===================================================================
--- head/net-mgmt/py3-dnsdiag/Makefile	(revision 451505)
+++ head/net-mgmt/py3-dnsdiag/Makefile	(revision 451506)
@@ -1,21 +1,28 @@
 # Created by: Babak Farrokhi <farrokhi@FreeBSD.org>
 # $FreeBSD$
 
 PORTNAME=	dnsdiag
 PORTVERSION=	1.6.3
 CATEGORIES=	net-mgmt python
 MASTER_SITES=	CHEESESHOP
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}
 
 MAINTAINER=	farrokhi@FreeBSD.org
 COMMENT=	DNS Diagnostics and measurement tools (ping, traceroute)
 
 LICENSE=	BSD2CLAUSE
 
 RUN_DEPENDS=	${PYTHON_PKGNAMEPREFIX}dnspython>=1.15.0:dns/py-dnspython \
 		${PYTHON_PKGNAMEPREFIX}cymruwhois>=1.6:net/py-cymruwhois
 
 USES=		python:3.3+
 USE_PYTHON=	autoplist distutils
 
-.include <bsd.port.mk>
+.include <bsd.port.pre.mk>
+
+.if defined(PACKAGE_BUILDING) && !defined(PACKAGE_BUILDING_FLAVORS) && \
+    ${PYTHON_VER} != ${PYTHON_DEFAULT}
+IGNORE=	you have python ${PYTHON_DEFAULT} set as the default, and this needs ${PYTHON_VER}
+.endif
+
+.include <bsd.port.post.mk>