diff --git a/science/polytope/Makefile b/science/polytope/Makefile
index b96b7928e664..983c12d09a54 100644
--- a/science/polytope/Makefile
+++ b/science/polytope/Makefile
@@ -1,37 +1,37 @@
 PORTNAME=	polytope
 DISTVERSION=	0.7.3-18
 DISTVERSIONSUFFIX=	-gcf83206
 CATEGORIES=	science
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	Library for generating Voronoi and Voronoi-like tessellations
 WWW=		https://github.com/LLNL/polytope
 
 LICENSE=	BSD3CLAUSE
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
 BUILD_DEPENDS=	${LOCALBASE}/include/boost/geometry.hpp:devel/boost-libs
 LIB_DEPENDS=	libsz.so:science/libaec
 
 USES=		cmake:testing
 USE_LDCONFIG=	yes
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	LLNL
 
-CXXFLAGS+=	-D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_NONE # prevent hardening issues with libc++
+CXXFLAGS+=	-D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_NONE # prevent hardening issues with libc++, see https://github.com/LLNL/polytope/issues/24
 
 CMAKE_ON=	BUILD_SHARED_LIBS
 CMAKE_OFF=	TESTING
 CMAKE_TESTING_ON=	TESTING
 
 OPTIONS_DEFINE=		SILO
 OPTIONS_DEFAULT=	SILO
 
 SILO_DESC=		Use SILO reader/writer
 SILO_CMAKE_BOOL=	USE_SILO
 SILO_LIB_DEPENDS=	libsiloh5.so:science/silo
 
 # tests as of 0.7.3-18: 96% tests passed, 1 tests failed out of 28
 
 .include <bsd.port.mk>