Index: Makefile
===================================================================
--- Makefile	(revision 480927)
+++ Makefile	(working copy)
@@ -8,7 +8,7 @@
 MAINTAINER=	kde@FreeBSD.org
 COMMENT=	Qt command-line interface to D-Bus
 
-USES=		qmake qt-dist:5,tools
+USES=		compiler:c++17-lang qmake qt-dist:5,tools
 USE_QT=		core dbus xml buildtools_build
 
 BUILD_WRKSRC=	${WRKSRC}/src/${PORTNAME}/${PORTNAME}