diff --git a/math/manifold/Makefile b/math/manifold/Makefile
index b0a58d18e12e..f15d9c8f5851 100644
--- a/math/manifold/Makefile
+++ b/math/manifold/Makefile
@@ -1,40 +1,47 @@
 PORTNAME=	manifold
 DISTVERSIONPREFIX=v
 DISTVERSION=	3.0.1
 CATEGORIES=	math cad
 
 MAINTAINER=	thierry@FreeBSD.org
 COMMENT=	Geometry library for topological robustness
 WWW=		https://github.com/elalish/manifold
 
 LICENSE=	APACHE20
 
 BUILD_DEPENDS=	glm>0:math/glm	\
 		googletest>0:devel/googletest
 LIB_DEPENDS=	libtbb.so:devel/onetbb	\
 		libClipper2.so:cad/Clipper2	\
 		libassimp.so:multimedia/assimp
 
 USES=		cmake compiler:c++17-lang pathfix
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	elalish
 
 CMAKE_ARGS=	-DMANIFOLD_FLAGS="${CFLAGS}"	\
 		-DMANIFOLD_PAR:STRING="NONE"
 CMAKE_ON=	BUILD_SHARED_LIBS	\
 		MANIFOLD_EXPORT		\
 		MANIFOLD_TEST
 CMAKE_OFF=	MANIFOLD_DOWNLOADS		\
 		MANIFOLD_JSBIND			\
 		MANIFOLD_CBIND			\
 		MANIFOLD_PYBIND			\
 		MANIFOLD_FUZZ			\
 		TRACY_ENABLE
 
 USE_LDCONFIG=	yes
 
+.include <bsd.port.options.mk>
+
+pre-configure:
+.if ${ARCH} == "i386" || ${ARCH} == "armv7"
+	${REINPLACE_CMD} -e 's|-Werror|-Wno-format|' ${WRKSRC}/CMakeLists.txt
+.endif
+
 do-test:
 	(cd ${BUILD_WRKSRC}/test && ./manifold_test)
 
 .include <bsd.port.mk>