With enough coding, you can "do anything" in any Turing complete language. This is meaningless. It doesn't mean it is advisable (simple, maintainable) to do so. C does not support a syntax for closures, so you'll really just be calling functions with an 'environment' arg or something similar. What's the point?

My point is that he claims C can't do closures or pass them either. Follow the thread.

As far as being turing complete, CSS is supposedly that, also, so good luck with that.

When people say a language supports closures, they are generally talking about syntax. C does not support a convenient syntax for closures, period.

Here's a guy who developed a closure "library" for C: https://nullprogram.com/blog/2017/01/08/

It's clever, but he actually had to resort to assembly...