[patch libstdc++]: Add some missing errno-constants for mingw-targets

[Kai Tietz]

2011/8/29 Paolo Carlini <paolo.carlini@oracle.com>:
> On 08/29/2011 10:54 AM, Pedro Alves wrote:
>>
>> While these two didn't get the HAVE_... prefix. Was that intended?
>
> To be clear: make sure before committing that *all* use _GLIBCXX_HAVE_*
>
> Paolo.

Done and added missing _GLIBCXX_HAVE_ for all checks.
Committed at revision 178257.

Thanks,
Kai