diff --git a/common/common.h b/common/common.h
new file mode 100644
index 0000000..fc2a2f9
--- /dev/null
+++ b/common/common.h
@@ -0,0 +1,3 @@
+#ifndef M_PI
+    #define M_PI 3.14159265358979323846
+#endif
diff --git a/decode_ft8.c b/decode_ft8.c
index 80db678..cac66b2 100644
--- a/decode_ft8.c
+++ b/decode_ft8.c
@@ -11,6 +11,7 @@
 #include "ft8/encode.h"
 #include "ft8/crc.h"
 
+#include "common/common.h"
 #include "common/wave.h"
 #include "common/debug.h"
 #include "fft/kiss_fftr.h"
diff --git a/gen_ft8.c b/gen_ft8.c
index a25cc30..efd873c 100644
--- a/gen_ft8.c
+++ b/gen_ft8.c
@@ -4,6 +4,7 @@
 #include <math.h>
 #include <stdbool.h>
 
+#include "common/common.h"
 #include "common/wave.h"
 #include "common/debug.h"
 #include "ft8/pack.h"
diff --git a/test.c b/test.c
index 6665259..f017adb 100644
--- a/test.c
+++ b/test.c
@@ -10,6 +10,7 @@
 #include "ft8/constants.h"
 
 #include "fft/kiss_fftr.h"
+#include "common/common.h"
 #include "common/debug.h"
 
 #define LOG_LEVEL LOG_INFO
@@ -155,4 +156,4 @@ int main()
     test4();
 
     return 0;
-}
\ No newline at end of file
+}