diff --git a/library/debug.c b/library/debug.c
index 9c8c2f6..a55324e 100644
--- a/library/debug.c
+++ b/library/debug.c
@@ -42,6 +42,7 @@
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
+#include "mbedtls/platform_util.h"
 
 #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
     !defined(inline) && !defined(__cplusplus)