diff --git a/archivers/zlib-ng/Makefile b/archivers/zlib-ng/Makefile
index 7381f615a448..d10a587b2a85 100644
--- a/archivers/zlib-ng/Makefile
+++ b/archivers/zlib-ng/Makefile
@@ -1,24 +1,26 @@
 PORTNAME=	zlib-ng
 DISTVERSION=	2.1.6
 CATEGORIES=	archivers
 
 MAINTAINER=	lbartoletti@FreeBSD.org
 COMMENT=	Fork of the zlib data compression library
 WWW=		https://github.com/zlib-ng/zlib-ng
 
 LICENSE=	ZLIB
 
-USES=		cmake compiler:c11
+USES=		cmake:${TESTING} compiler:c11
 USE_LDCONFIG=	yes
 USE_GITHUB=	yes
 
 OPTIONS_DEFINE=	SIMD TEST
 
 SIMD_CMAKE_BOOL=	WITH_OPTIM
 TEST_BUILD_DEPENDS=	googletest>=0:devel/googletest
+TEST_VARS=		TESTING=testing
 TEST_CMAKE_BOOL=	ZLIB_ENABLE_TESTS ZLIBNG_ENABLE_TESTS
-TEST_BROKEN=		error: use of undeclared identifier 'isascii'
+# error: use of undeclared identifier 'isascii'
+TEST_CFLAGS=		-D__XSI_VISIBLE
 
 PLIST_SUB=	SHLIB_VER=${DISTVERSION}
 
 .include <bsd.port.mk>