-/* Some systems don't have ENOSYS. */
-#ifndef ENOSYS
+/* Some systems don't have EOPNOTSUPP. */
+#ifndef EOPNOTSUPP
# ifdef ENOTSUP
-# define ENOSYS ENOTSUP
+# define EOPNOTSUPP ENOTSUP
# else
/* Some systems don't have ENOTSUP either. */
-# define ENOSYS EINVAL
+# define EOPNOTSUPP EINVAL
# endif
#endif