diff --git a/graphics/GraphicsMagick/Makefile b/graphics/GraphicsMagick/Makefile
index 0dd2d19b8981..8bd2b6c36163 100644
--- a/graphics/GraphicsMagick/Makefile
+++ b/graphics/GraphicsMagick/Makefile
@@ -118,3 +118,6 @@ regression-test: do-build
 		${MAKEFILE} ${MAKE_ARGS} check)
 
 .include <bsd.port.post.mk>
+# The OPENMP option may select gcc as compiler but on architectures
+# that have switched to libc++ clang should be used for C++ code.
+CXX=		c++