diff -up meshlab-2016.12/src/external/structuresynth-1.5/ssynth/SyntopiaCore/GLEngine/Raytracer/RayTracer.cpp.glu meshlab-2016.12/src/external/structuresynth-1.5/ssynth/SyntopiaCore/GLEngine/Raytracer/RayTracer.cpp
--- meshlab-2016.12/src/external/structuresynth-1.5/ssynth/SyntopiaCore/GLEngine/Raytracer/RayTracer.cpp.glu	2017-07-20 10:35:41.191316863 -0400
+++ meshlab-2016.12/src/external/structuresynth-1.5/ssynth/SyntopiaCore/GLEngine/Raytracer/RayTracer.cpp	2017-07-20 10:35:54.348009663 -0400
@@ -6,6 +6,7 @@
 #include "SyntopiaCore/Math/Vector3.h"
 #include "SyntopiaCore/Logging/Logging.h"
 #include "SyntopiaCore/Misc/MiniParser.h"
+#include <GL/glu.h>
 
 using namespace SyntopiaCore::Math;
 using namespace SyntopiaCore::Misc;
diff -up meshlab-2016.12/src/external/structuresynth-1.5/ssynth/SyntopiaCore/GLEngine/Sphere.h.glu meshlab-2016.12/src/external/structuresynth-1.5/ssynth/SyntopiaCore/GLEngine/Sphere.h
--- meshlab-2016.12/src/external/structuresynth-1.5/ssynth/SyntopiaCore/GLEngine/Sphere.h.glu	2017-07-20 10:36:14.442540470 -0400
+++ meshlab-2016.12/src/external/structuresynth-1.5/ssynth/SyntopiaCore/GLEngine/Sphere.h	2017-07-20 10:36:25.404284521 -0400
@@ -2,6 +2,7 @@
 
 #include "SyntopiaCore/Math/Vector3.h"
 #include "Object3D.h"
+#include <GL/glu.h>
 
 namespace SyntopiaCore {
 	namespace GLEngine {