I've had renewed interest in C recently, having been away from it for nearly 10 years. This renewed interest comes from working with golang for the last few years, and has caused me to find this book[0] which discusses ways to implement OOP ideas in pure C. Not to promote Go, or OOP, but rather I wonder if selecting useful idioms form modern languages wouldn't be a better intermediate step to updating C, then language level changes.

[0] https://www.cs.rit.edu/~ats/books/ooc.pdf