Index: head/math/tblis/Makefile
===================================================================
--- head/math/tblis/Makefile	(revision 494580)
+++ head/math/tblis/Makefile	(revision 494581)
@@ -1,37 +1,41 @@
 # Created by: Johannes M Dieterich <jmd@FreeBSD.org>
 # $FreeBSD$
 
 PORTNAME=	tblis
 PORTVERSION=	1.1.2
 DISTVERSIONPREFIX=	v
 CATEGORIES=	math
 
 MAINTAINER=	jmd@FreeBSD.org
 COMMENT=	Framework for performing tensor operations
 
 LICENSE=	BSD3CLAUSE
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
 BROKEN_aarch64=		fails to compile: include_configs.hpp:2:10: fatal error: 'configs/armv7a/config.hpp' file not found
 BROKEN_armv6=		fails to compile: include_configs.hpp:2:10: fatal error: 'configs/armv7a/config.hpp' file not found
 NOT_FOR_ARCHS=	i386
 NOT_FOR_ARCHS_REASON=	i386 requires SSE
 
 OPTIONS_DEFINE=	PARA
 PARA_DESC=	use pthread parallelization
 OPTIONS_DEFAULT=	PARA
 
 USES=		gmake libtool
 USE_LDCONFIG=	yes
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	devinamatthews
 
 HAS_CONFIGURE=	yes
 
 PARA_CONFIGURE_ON=	--enable-thread-model=pthreads
 PARA_CONFIGURE_OFF=	--enable-thread-model=none
 
 INSTALL_TARGET=	install-strip
 
+post-patch:
+# Avoid conflict with C++20 <version> by ignoring <...> under WRKSRC
+	@${REINPLACE_CMD} -i .c++20 's/-I/-iquote/g' ${WRKSRC}/Makefile.in
+
 .include <bsd.port.mk>