This is because we use libffi as a DLL and you can't statically reference dynamically loaded addresses on Windows.

You could change that format table to be initialised on first use, or resolve the FFI type lazily. Or change ctypes to statically link libffi (including updating our FFI build, which IIRC is the one that requires Cygwin, to generate static libraries instead of dynamic) - we can't backport this change, either, because it affects the layout on disk.