Is it possible to avoid global variables in a strictly procedural program?

A global variable is nothing but an implicit procedure argument. Make it explicit and the global variable goes away.

Note: the fact that you no longer use a global variable does not mean that you no longer use global state! What we did above was just a purely syntactical transformation, the semantics of the program haven't changed at all. It's just as non-composable, non-modular, non-threadsafe, non-parallelizable as it was before.

You can have variables on stack or in heap that will exist during all the program life.

Passing object style structure pointers to every function is a good way to have OO C coding style.

(I would suggest to have a look in linux sources)