Much more interesting is Mir: https://github.com/vnmakarov/mir

It has all the tools for custom JIT including a nice C compiler.

rcc[1] is another real-JIT C compiler. antcc[2] and xcc[3] are worth mentioning for being fast-enough to run C like scripting.

[1] https://github.com/dstogov/rcc

[2] https://codeberg.org/lsof/antcc

[3] https://github.com/tyfkda/xcc