Reworking the MSVC-related build options

[Tor Lillqvist]

> So please don't break free tool chain on windows:
>
> * non activated windows

How does not activating your Windows installation reduce the purchase
price of its license (if you mean "free as in beer", or make it less
proprietary (if you mean "free as in speech")? Or what are you saying
here?

Or is "non-activated" an euphemism for "pirated"? I better get out of
this discussion then before I say what I think.

Let's forget this whole idea.

--tml