diff --git a/library/x509_create.c b/library/x509_create.c
index ab87ac7..0a75c38 100644
--- a/library/x509_create.c
+++ b/library/x509_create.c
@@ -32,6 +32,8 @@
 #include "polarssl/asn1write.h"
 #include "polarssl/oid.h"
 
+#include <string.h>
+
 #if defined(_MSC_VER) && !defined strncasecmp && !defined(EFIX64) && \
     !defined(EFI32)
 #define strncasecmp _strnicmp