patch 9.0.0470: in :def function all closures in loop get the same variables

Problem:    In a :def function all closures in a loop get the same variables.
Solution:   When in a loop and a closure refers to a variable declared in the
            loop, prepare for making a copy of variables for each closure.

src/version.c

@@ -703,6 +703,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    470,
 /**/
     469,
 /**/