diff --git a/math/cln/Makefile b/math/cln/Makefile
index c6d28c62fd19..d66381a41000 100644
--- a/math/cln/Makefile
+++ b/math/cln/Makefile
@@ -1,31 +1,32 @@
 # Created by: Ying-Chieh Liao <ijliao@FreeBSD.org>
 
 PORTNAME=	cln
 PORTVERSION=	1.3.6
 CATEGORIES=	math devel
 MASTER_SITES=	http://www.ginac.de/CLN/ \
 		http://www.mirrors.wiretapped.net/security/cryptography/libraries/math/cln/ \
 		ftp://ftpthep.physik.uni-mainz.de/pub/gnu/
 
 MAINTAINER=	wen@FreeBSD.org
 COMMENT=	Class Library for Numbers
 
 LICENSE=	GPLv2
 LICENSE_FILE=	${WRKSRC}/COPYING
 
 LIB_DEPENDS=	libgmp.so:math/gmp
 
 GNU_CONFIGURE=	yes
 CONFIGURE_ARGS=	--with-gmp=${LOCALBASE}
 INSTALL_TARGET=	install-strip
+TEST_TARGET=	check
 USES=		compiler:c11 gmake libtool pathfix pkgconfig tar:bzip2
 USE_LDCONFIG=	yes
 
 INFO=		cln
 
 CPPFLAGS+=	${CPPFLAGS_${ARCH}}
 CPPFLAGS_aarch64=	-DNO_ASM
 CPPFLAGS_armv6=	-DNO_ASM
 CPPFLAGS_armv7=	-DNO_ASM
 
 .include <bsd.port.mk>
diff --git a/math/cln/files/patch-src_base_low_cl__low__div.cc b/math/cln/files/patch-src_base_low_cl__low__div.cc
index 15124551e323..a759e811a95b 100644
--- a/math/cln/files/patch-src_base_low_cl__low__div.cc
+++ b/math/cln/files/patch-src_base_low_cl__low__div.cc
@@ -1,11 +1,39 @@
 --- src/base/low/cl_low_div.cc.orig	2011-04-08 21:07:28 UTC
 +++ src/base/low/cl_low_div.cc
+@@ -10,11 +10,11 @@
+ // Implementation.
+ 
+ #ifdef NEED_VAR_divu_16_rest
+-uint16 divu_16_rest;
++extern "C" uint16 divu_16_rest;
+ #endif
+ 
+ #ifdef NEED_FUNCTION_divu_3216_1616_
+-uint16 divu_16_rest;
++extern "C" uint16 divu_16_rest = 0;
+ namespace cln {
+ #if 1
+ // Most processors have a good 32 by 32 bit division, use that.
+@@ -101,11 +101,11 @@ uint32 divu_3232_3232_(uint32 x, uint32 y)
+ #endif
+ 
+ #ifdef NEED_VAR_divu_32_rest
+-uint32 divu_32_rest;
++extern "C" uint32 divu_32_rest;
+ #endif
+ 
+ #ifdef NEED_FUNCTION_divu_6432_3232_
+-uint32 divu_32_rest;
++extern "C" uint32 divu_32_rest = 0;
+ namespace cln {
+ uint32 divu_6432_3232_(uint32 xhi, uint32 xlo, uint32 y)
+ // Methode:
 @@ -207,7 +207,7 @@ uint32 divu_6432_3232_(uint32 xhi, uint32 xlo, uint32 
  #endif
  
  #ifdef NEED_VAR_divu_64_rest
 -uint64 divu_64_rest;
 +extern "C" uint64 divu_64_rest = 0;
  #endif
  
  #ifdef NEED_FUNCTION_divu_6464_6464_
diff --git a/math/cln/files/patch-src_base_low_cl__low__mul.cc b/math/cln/files/patch-src_base_low_cl__low__mul.cc
index 8e8c48c4de2e..4b53103cb060 100644
--- a/math/cln/files/patch-src_base_low_cl__low__mul.cc
+++ b/math/cln/files/patch-src_base_low_cl__low__mul.cc
@@ -1,16 +1,30 @@
 --- src/base/low/cl_low_mul.cc.orig	2011-04-08 21:06:30 UTC
 +++ src/base/low/cl_low_mul.cc
+@@ -10,11 +10,11 @@
+ // Implementation.
+ 
+ #ifdef NEED_VAR_mulu32_high
+-uint32 mulu32_high;
++extern "C" uint32 mulu32_high;
+ #endif
+ 
+ #ifdef NEED_FUNCTION_mulu32_
+-uint32 mulu32_high;
++extern "C" uint32 mulu32_high = 0;
+ namespace cln {
+ uint32 mulu32_ (uint32 x, uint32 y)
+ {
 @@ -50,11 +50,11 @@ uint64 mulu32_w (uint32 arg1, uint32 arg2)
  
  
  #ifdef NEED_VAR_mulu64_high
 -uint64 mulu64_high;
 +extern "C" uint64 mulu64_high;
  #endif
  
  #ifdef NEED_FUNCTION_mulu64_
 -uint64 mulu64_high;
 +extern "C" uint64 mulu64_high = 0;
  namespace cln {
  extern "C" uint64 mulu64_ (uint64 x, uint64 y);
  uint64 mulu64_ (uint64 x, uint64 y)