patch 7.4.1518
Problem:    Channel with disconnected in/out/err is not supported.
Solution:   Implement it for Unix.
diff --git a/src/structs.h b/src/structs.h
index d70c024..7115ede 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -1417,8 +1417,8 @@
 #define JO_TIMEOUT_ALL	(JO_TIMEOUT + JO_OUT_TIMEOUT + JO_ERR_TIMEOUT)
 
 typedef enum {
+    JIO_PIPE,	    /* default */
     JIO_NULL,
-    JIO_PIPE,
     JIO_FILE,
     JIO_BUFFER,
     JIO_OUT