Index: head/devel/abseil/Makefile
===================================================================
--- head/devel/abseil/Makefile	(revision 559621)
+++ head/devel/abseil/Makefile	(revision 559622)
@@ -1,19 +1,21 @@
 # Created by: Alexey Dokuchaev <danfe@FreeBSD.org>
 # $FreeBSD$
 
 PORTNAME=	abseil
 PORTVERSION=	20200923.2
+PORTREVISION=	1
 CATEGORIES=	devel
 
 MAINTAINER=	danfe@FreeBSD.org
 COMMENT=	Abseil Common Libraries (C++)
 
 LICENSE=	APACHE20
 
 USES=		cmake compiler:c++11-lang
 USE_GITHUB=	yes
 GH_PROJECT=	${PORTNAME}-cpp
 
-CMAKE_ARGS=	-DBUILD_SHARED_LIBS:BOOL=ON
+CMAKE_ARGS=	-DBUILD_SHARED_LIBS:BOOL=ON \
+		-DCMAKE_CXX_STANDARD=17 # force the same highest C++ standard because of ABI differences: see https://github.com/abseil/abseil-cpp/issues/819
 
 .include <bsd.port.mk>