diff --git a/cad/meshlab/Makefile b/cad/meshlab/Makefile
index 3293ef172bb7..68e76e8a417e 100644
--- a/cad/meshlab/Makefile
+++ b/cad/meshlab/Makefile
@@ -14,7 +14,7 @@ LICENSE=	GPLv2
 BUILD_DEPENDS=	${LOCALBASE}/include/vcglib/img/img.h:devel/vcglib
 LIB_DEPENDS=	libmpirxx.so:math/mpir
 
-USES=		dos2unix gl qmake:outsource qt:5
+USES=		compiler:c++11-lang dos2unix gl qmake:outsource qt:5
 USE_GL=		gl glu glew
 USE_QT=		buildtools_build core gui network \
 		opengl script xml xmlpatterns widgets
diff --git a/cad/meshlab/files/patch-src_external_structuresynth-1.5_ssynth_SyntopiaCore_GLEngine_Raytracer_AtomicCounter.h b/cad/meshlab/files/patch-src_external_structuresynth-1.5_ssynth_SyntopiaCore_GLEngine_Raytracer_AtomicCounter.h
new file mode 100644
index 000000000000..4e3530cc5fca
--- /dev/null
+++ b/cad/meshlab/files/patch-src_external_structuresynth-1.5_ssynth_SyntopiaCore_GLEngine_Raytracer_AtomicCounter.h
@@ -0,0 +1,10 @@
+--- src/external/structuresynth-1.5/ssynth/SyntopiaCore/GLEngine/Raytracer/AtomicCounter.h.orig	2020-07-27 23:02:57 UTC
++++ src/external/structuresynth-1.5/ssynth/SyntopiaCore/GLEngine/Raytracer/AtomicCounter.h
+@@ -2,6 +2,7 @@
+ 
+ #include <QMutex>
+ #include <QWaitCondition>
++#include <climits>
+ 
+ namespace SyntopiaCore {
+ 	namespace GLEngine {