On windows you must download CMake from cmake.org and install it.
Given the option, you should choose to add CMake to the system PATH
However -- you must also remove it if present from your Cygwin installation.
The Cygwin version doesn't support MSVC.
(to be edited)
The way it works is that we define a project using a YAML file. The ruby scripts then generate the CMake file which generates the platform-native project file. The extra level of indirection gives us the ability to make the projects more human to edit, easier to maintain, and less susceptible to errors and bugs as compared with doing the CMake stuff directly.