diff --git a/inc/fdf.h b/inc/fdf.h
index 648b86d..2eb18f2 100644
--- a/inc/fdf.h
+++ b/inc/fdf.h
@@ -28,6 +28,9 @@
 # define FILE_ERROR "Error: could not open file %s\n"
 # define USAGE_ERROR "Usage: %s <filename>\n"
 
+#ifndef M_PI
+    #define M_PI 3.14159265358979323846
+#endif
 # define SQRT2 1.41421356237309514547
 # define SQRT6 2.44948974278317788134