Version of Windows

[Chris Teague]

This is probably trivial, but I'm having a tough time figuring out the
current version of Windows that Wine is mimicking.  I have a situation
where I need to behave differently if the version is NT (0x0500)
versus when it is XP (0x0600).  I see the WINVER #define, but that
doesn't seem right to me since this must be a runtime variable.  Can
someone point me at an example of how to tell what the current version
of Windows is?  Thanks,
Chris