diff --git a/src/Performance.c b/src/Performance.c
index e39c221..02244c9 100644
--- a/src/Performance.c
+++ b/src/Performance.c
@@ -4,6 +4,10 @@
 #include <math.h>
 #include <stdlib.h>
 
+#ifndef M_PI
+	#define M_PI 3.14159
+#endif
+
 enum {
 	DmInt_DEFAULT_TEMPO = 100,
 	DmInt_DEFAULT_SAMPLE_RATE = 44100,