Build Python from CMake

Getting Python can be tricky for license-restricted users e.g. government and corporations. Building Python can be an arcane process without the automation of a high-level build system CMake. Python uses Autotools on most platforms except Windows where Visual Studio is used. The libraries need to be built with specific options and the forums are full of suggestions for tweaking Python build scripts etc.

Our CMake project to build Python elides those issues for Linux/macOS platforms at least. It builds basic requirements of Python including expat, ffi, bzip2, xz, readline, zlib and more.