Re: Windows XP support

> On the other hand, I know somebody who got it working on Windows 98 by
> just using KernelEx and a few extra stub functions, so it looks like
> SDL2 is barely even doing much with XP.

XP added a handful of nice features (like RAWINPUT), but Win32, so far, 
hasn't been the constant tension of dropping old platforms like macOS 
has been. 90% of what we need has been in Win32 since Windows NT 3.51, 
much of the rest was officially backported by Microsoft (like XInput) or 
can be dynamically loaded with reasonable fallbacks for older systems 
(like the Shell APIs).

The Win9x OSes got dropped partially because they were ancient and 
largely abandoned (whereas WinXP, while old, was still popular), and 
NT-based OSes like Windows XP had guaranteed Unicode support, which 
meant we didn't need two codepaths through everything or any 
understanding of what a "codepage" is, which simplifies our work immensely.

We could drop XP at some point, but there's not a lot of pressure to do 
so, at least until (and if!) the UWP model gets wide, wide, wide 
adoption. On Mac OS X, we were falling into this gross maze of #ifdefs 
and version checks and evaporating compiler support and stuff, and that 
forces our hand a lot, but Windows hasn't been like that.

--ryan.