M_PI diff for output_example (handles undefined M_PI) by (Bill Eldridge <bill at rfa dot org>)

Originally committed as revision 2175 to svn://svn.ffmpeg.org/ffmpeg/trunk

output_example.c

@@ -26,6 +26,10 @@
 #include <stdio.h>
 #include <math.h>
 
+#ifndef M_PI
+#define M_PI 3.1415926535897931
+#endif
+
 #include "avformat.h"
 
 /* 5 seconds stream duration */