mmap fixes

[Ken Brown]

On 12/18/2024 12:16 PM, Ken Brown wrote:
> The two attached patches fix the bugs reported in
> 
>   https://cygwin.com/pipermail/cygwin/2024-December/256911.html
> 
> and
> 
>    https://cygwin.com/pipermail/cygwin/2024-December/256913.html
> 
> The second one is still under discussion on the cygwin list and may turn 
> out to be wrong.
I forgot to say that I was unable to determine when the bugs were 
introduced.  They seem to go way back.  Can I just omit the "Fixes" line?

Ken