1. Get FINK and install the SDL libraries.
2. make -f Makefile.OSX
You should see some warnings, but it should compile. I also compiled with XCode, but I prefer not to use ide-s.

Mac OS X Notes:
-SDL or OpenGL seems to reverse the mouse pointer's Y coord. when running in windowed mode. I added code to work around this but I suspect this code will have to be removed in the future.

1. Make sure you have SDL, OpenGL and GLUT libraries installed.
2. Get CMake and run: "cmake .". CMake supposedly runs on windows and the mac but I couldn't get those platforms to compile "out of the box". I still have regular Makefiles around, use those if you can't get cmake to work.
3. make
I run Mandrake linux 9.2, so older versions of gcc may give you problems.

Linux notes:
-To check that you're running in hardware accelerated mode, type "glxinfo". Look for a line like "Direct rendering". If the value is "yes", you're ok.

1. Install MinGW and MSYS (In that order!)
2. Install GLUT for MinGW
3. Install SDL for windows
4. In MSYS, type: "make -f Makefile.win32"

Windows notes:
The hardest thing on windows is to get your compilation environment set up... I usually install Mingw, Msys in that order. You need to get special mingw versions of sdl and glut. Unzip and put the libraries/headers in every lib/header directory you can think of. For good measure, I usually put the .dll files in the windows system folder as well. Then, unzip scourge in msys/1.0/home/ and try to compile. If mingw/msys is configured correctly, you should not have any other problems.

Daroth-U reported having to add:
#defined GLUT_DISABLE_ATEXIT_HACK
to constants.h.