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

[David Spickett via cfe-commits]

DavidSpickett wrote:

> I will get you instructions on how to do that (will be tomorrow at this point).

https://github.com/llvm/llvm-project/issues/94741#issuecomment-2154656315

There is some underlying issue (https://github.com/llvm/llvm-project/issues/94741), so if you want to try and fix it, that's great, but it's also fine if you'd rather wait and see what I find on native hardware.

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