diff --git a/Secp256k1.xs b/Secp256k1.xs
index 6f201a4..e42e6eb 100644
--- a/Secp256k1.xs
+++ b/Secp256k1.xs
@@ -3,6 +3,8 @@
 #include "perl.h"
 #include "XSUB.h"
 
+#include "ppport.h"
+
 #include <secp256k1.h>
 
 #define CURVE_SIZE 32