patch 7.4.1522

Problem:    Cannot write channel err to a buffer.
Solution:   Implement it.

src/version.c

@@ -743,6 +743,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1522,
 /**/
     1521,
 /**/