--- ./test/v3ext.c	2022-07-05 11:08:33.000000000 +0200
+++ ./test/v3ext.c	2022-10-18 13:58:05.000000000 +0200
@@ -8,6 +8,7 @@
  */
 
 #include <stdio.h>
+#include <string.h>
 #include <openssl/x509.h>
 #include <openssl/x509v3.h>
 #include <openssl/pem.h>