I want to build an open source OS based on Apple's open source Darwin code, but I can't find any useful documentation about this. Some open source projects, such as PureDarwin and Darwin, are rather obsolete, so how can I build a Darwin OS based on Darwin's source code?
If building a bootable image is difficult, I'd like to try building a Darwin userland without the OS kernel first.
I'm not trying to be Mackintosh because I know it's against the EULA. So I just want to use the open source code to do my job.