fix r1921
diff --git a/src/os/unix/ngx_linux_config.h b/src/os/unix/ngx_linux_config.h
index c584ff8..cd93509 100644
--- a/src/os/unix/ngx_linux_config.h
+++ b/src/os/unix/ngx_linux_config.h
@@ -69,7 +69,7 @@
 #endif
 
 
-#if (NGX_HAVE_POLL)
+#if (NGX_HAVE_POLL || NGX_HAVE_RTSIG)
 #include <poll.h>
 #endif