I guess you can do that, but if for some reason you needed to compile separately, (suppose you sell the system to a third party to a client, and they need to modify module 1, module 2 and the main loop.) It would be pretty trivial to remove some #include "module3.c" lines and add some -o module3 options to the compiler. Right?

I'm not sure what Rust or docker have to do with this basic issue, it just feels like young blood attempting 2020 solutions before exploring 1970 solutions.