patch 7.4.1891

Problem:    Channel reading very long lines is slow.
Solution:   Collapse multiple buffers until a NL is found.

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1891,
 /**/
     1890,
 /**/