patch 8.0.1774: reading very long lines can be slow

Problem:    Reading very long lines can be slow.
Solution:   Read up to 1 Mbyte at a time to avoid a lot of copying.  Add a
            check for going over the column limit.

src/version.c

@@ -761,6 +761,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1774,
 /**/
     1773,
 /**/