There's no way to make C modern language without breaking all the legacy code. But if possible, I would remove the preprocessor and cover its usage in core lang

There's no way to make C modern language without breaking all the legacy code. But if possible, I would remove the preprocessor and cover its usage in core language. For projects where you are free to choose your language, Nim is very modern and powerful. It compiles to C so you can use it as easy replacement.