Today I've read CMake documentation and after several hours of figuring things out (without prior experience) I was able to generate valid VS7.1 project from the old code and build it (I suppose that I could generate project files for other VS versions too). It turned out that CMake is really nice and straightforward tool. The only thing to worry about is (as it is in my case) to detect current environment/platform/build type (eg. debug/release), set up paths to external libraries and include directories, link external libraries with our target executable and that's all.
Now I have to add two automated steps: copying proper dynamic libraries to folders with build targets on win32 platform, automated generation of doxygen documentation and maybe copying data/resources needed by engine from other folders (be it textures, mesh, sound data ...).
If it comes to source code it needs some clean up, minor rearranging and heavy debugging. I have to add javadoc style comments (atm I don't really remember what I've written several years ago). Also win32 api code is the thing that I would like to go away and I would like to replace it with something more generic/portable (like, for example, text based configuration file ;))) ).