patch 8.2.3246: memory use after free

Problem:    Memory use after free.
Solution:   When clearing a string option set the pointer to "empty_option".
diff --git a/src/option.c b/src/option.c
index 182ff34..decba50 100644
--- a/src/option.c
+++ b/src/option.c
@@ -807,7 +807,7 @@
 	else if (options[i].var != VAR_WIN
 		&& (options[i].flags & P_STRING))
 	    // buffer-local option: free global value
-	    free_string_option(*(char_u **)options[i].var);
+	    clear_string_option((char_u **)options[i].var);
     }
 }
 #endif
diff --git a/src/version.c b/src/version.c
index 6b37200..7710018 100644
--- a/src/version.c
+++ b/src/version.c
@@ -756,6 +756,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3246,
+/**/
     3245,
 /**/
     3244,