L"日本語"

    case 'a': ... case 'z':
    case 'A': ... case 'Z':
    case '_':
    parse_ident_fast:
        ...
    case 'L':
        t = p[1];
        if (t != '\\' && t != '\'' && t != '\"') {
            /* fast case */
            goto parse_ident_fast;
        } else {
            PEEKC(c, p);
            if (c == '\'' || c == '\"') {
                is_long = 1;
                goto str_const;
            } else {
                cstr_reset(&tokcstr);
                cstr_ccat(&tokcstr, 'L');
                goto parse_ident_slow;
            }
        }
        break;