#2890: support os.O_ASYNC and fcntl.FASYNC.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 6a72166..a4bbac5 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -8756,6 +8756,11 @@
 #endif
 
 /* GNU extensions. */
+#ifdef O_ASYNC
+        /* Send a SIGIO signal whenever input or output 
+           becomes available on file descriptor */
+        if (ins(d, "O_ASYNC", (long)O_ASYNC)) return -1;
+#endif
 #ifdef O_DIRECT
         /* Direct disk access. */
         if (ins(d, "O_DIRECT", (long)O_DIRECT)) return -1;