added WALBERLA_OVERRIDE to wrap c++11 override

src/core/Macros.h

@@ -39,6 +39,12 @@
 #define WALBERLA_PRAGMA(x) _Pragma(#x)
 #endif
 
+#ifndef WALBERLA_CXX_COMPILER_IS_IBM
+#define WALBERLA_OVERRIDE
+#else
+#define WALBERLA_OVERRIDE override
+#endif
+
 // macro overloading (-> https://stackoverflow.com/a/24028231)
 
 #define WALBERLA_GLUE(x, y) x y