diff --git a/3rdparty/everest/library/Hacl_Curve25519_joined.c b/3rdparty/everest/library/Hacl_Curve25519_joined.c
index ee62be1..49d4b48 100644
--- a/3rdparty/everest/library/Hacl_Curve25519_joined.c
+++ b/3rdparty/everest/library/Hacl_Curve25519_joined.c
@@ -18,6 +18,12 @@
  *
  *  This file is part of mbed TLS (https://tls.mbed.org)
  */
+#ifndef _BSD_SOURCE
+#define _BSD_SOURCE
+#endif
+#ifndef _DEFAULT_SOURCE
+#define _DEFAULT_SOURCE
+#endif
 
 #include "common.h"