diff --git a/winsup/cygwin/include/sys/poll.h b/winsup/cygwin/include/sys/poll.h
index 822827825..0da4c3f03 100644
--- a/winsup/cygwin/include/sys/poll.h
+++ b/winsup/cygwin/include/sys/poll.h
@@ -39,9 +39,11 @@ struct pollfd {
 typedef unsigned int nfds_t;
 
 extern int poll __P ((struct pollfd *fds, nfds_t nfds, int timeout));
+#if __GNU_VISIBLE
 extern int ppoll __P ((struct pollfd *fds, nfds_t nfds,
 		       const struct timespec *timeout_ts,
 		       const sigset_t *sigmask));
+#endif
 
 __END_DECLS