[clang] [clang-repl] Lay the foundation of pretty printing for C. (PR #89811)

[Vassil Vassilev via cfe-commits]

vgvassilev wrote:

> > Would dropping this conditional make it work for your case?
> 
> I don't have a mac handy to try it right now. If you commit it, our system will test it automatically :) Or maybe @Thakis could give it a try?

I am on my phone in the next couple of hours and I am not sure how to reproduce it. Maybe somebody who can should give it a shot?

https://github.com/llvm/llvm-project/pull/89811