diff --git a/samples/rotate/rotate.cpp b/samples/rotate/rotate.cpp
index 3319489b51..4b309651bd 100644
--- a/samples/rotate/rotate.cpp
+++ b/samples/rotate/rotate.cpp
@@ -22,7 +22,14 @@
 
 #include "wx/image.h"
 
+/* GRG: This is not ANSI standard, define M_PI explicitly
 #include <math.h>       // M_PI
+*/
+
+#ifndef M_PI
+#define M_PI 3.1415926535897932384626433832795
+#endif
+
 
 class MyApp: public wxApp
 {