rework structure

hifive1-vp/hello/bsp/libwrap/sys/link.c

@@ -0,0 +1,9 @@
+/* See LICENSE of license details. */
+
+#include <errno.h>
+#include "stub.h"
+
+int __wrap_link(const char *old_name, const char *new_name)
+{
+  return _stub(EMLINK);
+}