diff --git a/plugins/common.h b/plugins/common.h
index 09af7e7e..c0dc2f41 100644
--- a/plugins/common.h
+++ b/plugins/common.h
@@ -141,6 +141,7 @@
 #ifdef HAVE_GNUTLS_OPENSSL_H
 #  include <gnutls/openssl.h>
 #else
+#  define OPENSSL_LOAD_CONF /* See the OPENSSL_config(3) man page. */
 #  ifdef HAVE_SSL_H
 #    include <rsa.h>
 #    include <crypto.h>