patch 8.0.0535: memory leak when exiting from within a user function

Problem:    Memory leak when exiting from within a user function.
Solution:   Clear the function call stack on exit.
diff --git a/src/version.c b/src/version.c
index 4e91f14..9818719 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    535,
+/**/
     534,
 /**/
     533,