gcc.c (print_file_name, [...]): Qualify a char* with the `const' keyword.

        * gcc.c (print_file_name, print_prog_name, spec_machine,
        read_specs, set_spec, lookup_compiler, build_search_list,
        putenv_from_prefixes, find_a_file, record_temp_file,
        delete_if_ordinary, handle_braces, do_spec, do_spec_1, find_file,
        is_directory, validate_switches, used_arg, default_arg,
        pfatal_with_name, perror_with_name, pfatal_pexecute, fatal, error,
        notice, add_preprocessor_option, add_assembler_option,
        add_linker_option, process_command, execute,
        unused_prefix_warnings, clear_args, fatal_error,
        lang_specific_driver, user_specs, compiler, link_command_spec,
        option_map, translate_options, make_temp_file, temp_name,
        programname, path_prefix, machine_suffix, just_machine_suffix,
        gcc_exec_prefix, standard_exec_prefix, standard_exec_prefix_1,
        md_exec_prefix, md_startfile_prefix, md_startfile_prefix_1,
        standard_startfile_prefix, standard_startfile_prefix_1,
        standard_startfile_prefix_2, tooldir_base_prefix, tooldir_prefix,
        multilib_dir, temp_filename, temp_file, command, switchstr,
        infile, outfiles, input_filename, input_basename, input_suffix,
        check_live_switch, main): Qualify a char* with the `const' keyword.

From-SVN: r25676