diff --git a/externals/lyonpotpourri/m_pd.h b/externals/lyonpotpourri/m_pd.h
index 02030a7796b5325b3013b1a73f266b9276bc81e2..c29bc79b63f8dcb3175444af243e6abc7debd341 100755
--- a/externals/lyonpotpourri/m_pd.h
+++ b/externals/lyonpotpourri/m_pd.h
@@ -81,8 +81,12 @@ typedef unsigned __int64  uint64_t;
 
 /* signed and unsigned integer types the size of a pointer:  */
 #if !defined(PD_LONGINTTYPE)
+#if defined(_WIN32) && defined(_WIN64)
+#define PD_LONGINTTYPE long long
+#else
 #define PD_LONGINTTYPE long
 #endif
+#endif
 
 #if !defined(PD_FLOATSIZE)
   /* normally, our floats (t_float, t_sample,...) are 32bit */