patch 7.4.1318
Problem:    Channel with pipes doesn't work in GUI.
Solution:   Register input handlers for pipes.
diff --git a/src/os_unix.c b/src/os_unix.c
index 01b5a93..65a4b92 100644
--- a/src/os_unix.c
+++ b/src/os_unix.c
@@ -5116,10 +5116,15 @@
     close(fd_err[1]);
     channel_set_pipes(channel, fd_in[1], fd_out[0], fd_err[0]);
     channel_set_job(channel, job);
+#ifdef FEAT_GUI
+    channel_gui_register(channel);
+#endif
 
     return;
 
 failed:
+    if (channel != NULL)
+	channel_free(channel);
     if (fd_in[0] >= 0)
     {
 	close(fd_in[0]);