Are you still looking?
I'm a C/C++ programmer, though I haven't coded in years, but I'm willing to try..
I was more interested in some todo post I saw about the visibility of enemies (and allies) though.. . Although it sounds a bit difficult.
From what I recall of posts I read about your Radiant library is UFORadiant is about 10-12 times slower than GKTRadiant, so I have no idea what you really want done... This is something I can probably handle since I am a bit above average for speeding up programs (not much above average mind you).
I use MSVC 6.0 however, so from other posts, I suspect I won't be able to compile something as big as the game, but maybe I can see the Radiant code.
In the stable version, I keep losing enemies on maps too, and despite days of searching, I couldn't find the discussions indicating what is happening except for a short comment about aliens falling through a floor. Oh, my own guys fall through the sloping floor and can't move anymore in the Rocky Mountain map.
I know absolutely nothing about Linux, how it works, or what it does, other than it's some free operating system.
I think the last point mentioned is how I'm supposed to say how much I love this great game, but I have barely played it actually, and while what I saw looked nice, it definitely needs a way to not see enemies all the way across the map so well. I'd be happy to try to fix this, but I really have no idea how - save a few posts on the todo for visibility that I saw, but lost again, something about 10 lines raytraced to arms, legs, chest, head, etc. I have no idea what raytracing is all about except for the google definition though. My expertise is windows applications programming, not games. It looked nice though, but I can't find it again, and it may be too difficult to start with.