updated for version 7.4.609

Problem:    For complicated list and dict use the garbage collector can run
            out of stack space.
Solution:   Use a stack of dicts and lists to be marked, thus making it
            iterative instead of recursive. (Ben Fritz)

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    609,
 /**/
     608,
 /**/