Index: head/security/py-certifi/Makefile
===================================================================
--- head/security/py-certifi/Makefile	(revision 449724)
+++ head/security/py-certifi/Makefile	(revision 449725)
@@ -1,19 +1,19 @@
 # Created by: Olivier Duchateau <duchateau.olivier@gmail.com>
 # $FreeBSD$
 
 PORTNAME=	certifi
 PORTVERSION=	2017.7.27.1
 CATEGORIES=	security python
 MASTER_SITES=	CHEESESHOP
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}
 
 MAINTAINER=	python@FreeBSD.org
 COMMENT=	Mozilla SSL certificates
 
 LICENSE=	MPL20
 
 NO_ARCH=	yes
 USES?=		python
-USE_PYTHON=	autoplist distutils
+USE_PYTHON=	autoplist concurrent distutils
 
 .include <bsd.port.mk>