strncasecmp bugfix and improvements

[Jeff Johnston]

Patch checked in.

-- Jeff J.

Wizards' Guild wrote:
> Jeff,
>
> Here is the patch I've owed for some days... the recent topic jogged my memory.
>
> On Apr 6 21:14, Wizards' Guild wrote:
>   
>> Thanks! I hadn't expected such a quick response! :)
>>
>> Here are the other routines changed similarly. The first gets a similar 
>> performance improvement; the others are changed only to avoid passing 
>> negative values to toupper/tolower. I have _ansi'fied this time.
>>
>> The docs for both strcasecmp and strncasecmp say "after both are converted 
>> to uppercase" - this is wrong, because both are converted to lowercase.
>>     
>
> Note that strncasecmp.c is also changed to correct the minor documentation error.
>
>         * libc/string/strcasecmp.c: Optimized rewrite.
>         * libc/string/strlwr.c: Avoid passing signed char to tolower.
>         * libc/string/strupr.c: Avoid passing signed char to tolower.
>
> ---
> Mike Burgess
> Avanex Corporation
> 607-562-7169
>