[Development] Having a reserved value for the platform enums was RE: Binary incompatible changes to Qt 4.8

[Shaw Andy]

[snip]

> >The warning needs to go away, at least, provided that Qt *is* tested on
> >Windows 8. Whether we add the enum or not, that's a bit orthogonal.
> 
> Yes, the warning needs to be fixed.
> 
> But I don't have any problems with adding the new enum in a patch level
> release. The only thing it can break is that your code won't compile
> against 4.8.1 anymore if you use it. This is really one of these cases
> where we should make a small exception to our rule of not adding any API
> to a patch level release.
> 
> Please go ahead and back port the change to 4.8.

Since this could easily be a problem again in the future should we consider having a reserved value for the Windows and Mac platform version enums?  That way should it be decided that we want to add support for a new version of a platform in a maintenance release we could easily utilize the reserved one and then bump up the reserved one in the next minor release. 

Andy