Object-orientation in C

Question

What would be a set of nifty preprocessor hacks (ANSI C89/ISO C90 compatible) which enable some kind of ugly (but usable) object-orientation in C?

I am familiar with

Answer 1

Another way to program in an object oriented style with C is to use a code generator which transforms a domain specific language to C. As it's done with TypeScript and JavaScript to bring OOP to js.