diff --git c/math/cln/Makefile i/math/cln/Makefile
index 52cdbd331088..1f6bde635dc4 100644
--- c/math/cln/Makefile
+++ i/math/cln/Makefile
@@ -21,8 +21,6 @@ USE_LDCONFIG=	yes
 
 INFO=		cln
 
-BROKEN_aarch64=	Fails to compile: error: declaration of divu_64_rest in global scope conflicts with declaration with C language linkage
-
 .include <bsd.port.pre.mk>
 
 .if ${ARCH} == aarch64 || ${ARCH} == armv6 || ${ARCH} == armv7
diff --git c/math/cln/files/patch-src_base_low_cl__low__div.cc i/math/cln/files/patch-src_base_low_cl__low__div.cc
new file mode 100644
index 000000000000..fa6c2c78daf9
--- /dev/null
+++ i/math/cln/files/patch-src_base_low_cl__low__div.cc
@@ -0,0 +1,11 @@
+--- src/base/low/cl_low_div.cc.orig	2018-06-23 21:13:46 UTC
++++ src/base/low/cl_low_div.cc
+@@ -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;
+ #endif
+ 
+ #ifdef NEED_FUNCTION_divu_6464_6464_
diff --git c/math/cln/files/patch-src_base_low_cl__low__mul.cc i/math/cln/files/patch-src_base_low_cl__low__mul.cc
new file mode 100644
index 000000000000..ecdb7c70891c
--- /dev/null
+++ i/math/cln/files/patch-src_base_low_cl__low__mul.cc
@@ -0,0 +1,16 @@
+--- src/base/low/cl_low_mul.cc.orig	2018-06-23 21:15:19 UTC
++++ src/base/low/cl_low_mul.cc
+@@ -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;
+ namespace cln {
+ extern "C" uint64 mulu64_ (uint64 x, uint64 y);
+ uint64 mulu64_ (uint64 x, uint64 y)