MINOR: cli/threads: make "show fd" report thread_sync_io_handler instead of "unknown"
The output was confusing when the sync point's dummy handler was shown.
This patch should be backported to 1.8 to help with troubleshooting.
diff --git a/src/hathreads.c b/src/hathreads.c
index fd0eb68..0d0b376 100644
--- a/src/hathreads.c
+++ b/src/hathreads.c
@@ -33,7 +33,9 @@
#endif
/* Dummy I/O handler used by the sync pipe.*/
-static void thread_sync_io_handler(int fd) { }
+void thread_sync_io_handler(int fd)
+{
+}
/* Initializes the sync point. It creates a pipe used by threads to wakup all
* others when a sync is requested. It also initialize the mask of all create