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Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/3rdparty/everest/library/Hacl_Curve25519_joined.c b/3rdparty/everest/library/Hacl_Curve25519_joined.c
index 49d4b48..149e474 100644
--- a/3rdparty/everest/library/Hacl_Curve25519_joined.c
+++ b/3rdparty/everest/library/Hacl_Curve25519_joined.c
@@ -19,7 +19,7 @@
* This file is part of mbed TLS (https://tls.mbed.org)
*/
#ifndef _BSD_SOURCE
-#define _BSD_SOURCE
+#define _BSD_SOURCE /* Required to enable compilation under --std=c99 */
#endif
#ifndef _DEFAULT_SOURCE
#define _DEFAULT_SOURCE