diff --git a/stepmania/src/global.h b/stepmania/src/global.h
index 76e1c15a74..129c2c78cb 100644
--- a/stepmania/src/global.h
+++ b/stepmania/src/global.h
@@ -145,6 +145,11 @@ typedef StdString::CStdString RString;
 
 /* Define a few functions if necessary */
 #include <cmath>
+
+#ifndef M_PI
+#define M_PI 3.1415926535897932384626433832795
+#endif
+
 #ifdef NEED_POWF
 inline float powf( float x, float y ) CONST_FUNCTION;
 float powf( float x, float y ) { return float( pow(double(x), double(y)) ); }