diff --git a/library/error.c b/library/error.c
index cba61e9..0d9f736 100644
--- a/library/error.c
+++ b/library/error.c
@@ -19,7 +19,7 @@
 
 #include "common.h"
 
-#if defined(MBEDTLS_ERROR_STRERROR_DUMMY)
+#if defined(MBEDTLS_ERROR_C)
 #include <string.h>
 #endif