patch 7.4.1789
Problem:    Cannot use ch_read() in the close callback.
Solution:   Do not discard the channel if there is readahead.  Do not discard
            readahead if there is a close callback.
diff --git a/src/version.c b/src/version.c
index 55b1650..9f311ac 100644
--- a/src/version.c
+++ b/src/version.c
@@ -754,6 +754,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1789,
+/**/
     1788,
 /**/
     1787,