jart/cosmopolitan ? reverse-engineered prompt

I want this repo set up so I can use it as a build once, run anywhere C and C++ toolchain. Please get the project building from source with the existing make setup, let it fetch whatever compiler bundle it needs, and make sure there is a simple working example like hello world that I can compile and run.

The main goal is that I can produce one native executable that works across Linux, Mac, Windows, FreeBSD, OpenBSD, and NetBSD, using this project’s approach. Please also include the basic developer quality of life stuff shown in the docs, like how to run a program with system call tracing and function tracing, and where logs go. If Linux needs the APE loader installed for smooth execution, wire that up or at least make it easy and obvious. I would also like one small test target built and runnable so I know the toolchain is healthy. Keep it practical and runnable from the repo root, and look up current docs online if you need to.