So, I downloaded the 3.2.1 source, shoved it in my D: drive, loaded up the VB command prompt and decided to give it a try. No luck. It complains that it cannot find included file windows.h and then tells me, in no uncertain terms, that I should go back to Natural Selection mapping.
For those interested, here's a screenshot. Sorry Lynx users. As you can see, I highlighted the error message.

So, any idea how to get this working? (I tried commenting out the windows.h bit in unreal.c to see what would happen - I've never seen a bigger load of compile errors in my life.)