patch 7.4.1021

Problem:    Some makefiles are outdated.
Solution:   Add a note to warn developers.

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1021,
 /**/
     1020,
 /**/