Fix minor type confusion

* src/tar.c (decode_options): Don’t assign ‘false’ to a pointer.

src/tar.c

@@ -2632,7 +2632,7 @@ decode_options (int argc, char **argv)
       if (optloc_eq (preserve_order_loc, listed_incremental_loc))
 	option_conflict_error ("--preserve-order", "--listed-incremental");
       else if (preserve_order_loc->source == OPTS_COMMAND_LINE)
-	listed_incremental_option = false;
+	listed_incremental_option = NULL;
       else
 	same_order_option = false;
     }