patch 9.0.0530: using freed memory when autocmd changes mark

Problem:    Using freed memory when autocmd changes mark.
Solution:   Copy the mark before editing another buffer.

src/version.c

@@ -699,6 +699,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    530,
 /**/
     529,
 /**/