RFR: 8150688: Fix os_windows siglabel

[Kim Barrett]

> On Mar 1, 2016, at 10:38 PM, David Holmes <david.holmes at oracle.com> wrote:
>> Made some other nearby cleanups while we're here, including misuse of
>> struct siglable in get_signal_number.
> 
> Ah - my bad on the review of that one. Not sure why we didn't just reuse "struct siglabel" instead of defining an anonymous struct. Was it actually incorrect or just odd looking?

The structs *were* structurally identical, so it was only odd.

> Ship it!

Thaks, David.