patch 8.1.1563: crash when using closures

Problem:    Crash when using closures.
Solution:   Set reference in varlist of funccal when running the garbage
            collector. (Ozaki Kiichi, closes #4554, closes #4547)

src/version.c

@@ -777,6 +777,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1563,
 /**/
     1562,
 /**/