[sldev] SDL on win32

[Gareth Nelson]

I've been pondering why this is not used........ SDL is designed for
being cross-platform, yet the viewer only uses it on linux. If SDL was
used on all platforms instead then it would make certain tasks a lot
simpler (say for example that firefox plugin i've been working on).

So, before I waste time messing around with this - is there any reason
SDL is not already used for the other platforms?