* Note the conspicuous absence of ctype macros in these definitions.  On
     * non-ASCII hosts, we can't depend on string literals or ctype macros to
     * tell us anything about network-format data.  The rest of the BIND system
     * is not careful about this, but for some reason, we're doing it right here.

Well that is only a problem if the charset is converted to something else. Are there still systems out there without a C compiler that can be told to use ASCII?