* tree.c (tree_node_kind_names, print_obstack_name,
        get_identifier, maybe_get_identifier, build_string,
        build_expr_wfl, is_attribute_p, lookup_attribute,
        print_obstack_statistics, get_file_function_name_long, tree_check,
        tree_class_check, expr_check): Qualify a char* with the `const'
        keyword.
        * tree.h (get_identifier, maybe_get_identifier, build_string,
        build_expr_wfl, is_attribute_p, lookup_attribute,
        print_obstack_statistics, print_obstack_name, tree_check,
        tree_class_check, expr_check): Likewise.

From-SVN: r25261