odin-lang/odin ? reverse-engineered prompt

Build me the Odin programming language project so it can be compiled from source and run on my machine.

I want a working developer setup for the compiler, standard libraries, and example programs, with clear build instructions for Windows, Linux, and macOS. Make sure the repository can be checked out and built without me having to guess what to do, and add or fix anything needed so the main build scripts work smoothly.

If you need current install or dependency details, look them up online and use the latest docs. After that, make sure I can build the compiler, run a few examples, and see that the language is working end to end. If there are missing pieces in the repo, please fill them in in the simplest way that matches the existing project.