Genghis is written in C#. Building Genghis requires Visual C# or Visual Studio.NET.
Visual Studio.NET solution and project files (*.sln and *.csproj) are provided to build Genghis and all the samples. You should be able to load any solution file into Visual C#/Visual Studio.NET and build the project for yourself.
A NAnt build script (Genghis.build) is also provided. It is used to make the snapshot for Genghis, and is not designed for general use. You may wish to use this file to simulate the snapshot build process; please be aware that you will not be able to properly sign the release mode Genghis DLL (the private key is not provided in this distribution).
For Visual Studio.NET related build issues, please contact the Off Topic Windows mailing list. This is where the Genghis contributors have their discussions, and most of them will be familiar with Visual Studio.NET builds of Genghis.
If you have NAnt related build issues, you should contact Brad Wilson (the Genghis build master) directly.