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

[Vassil Vassilev via cfe-commits]

vgvassilev wrote:

> It's broken here https://lab.llvm.org/buildbot/#/builders/236/builds/11633

It seems broken for a different reason. Somehow we did not export that `__clang_Interpreter_SetValueNoAlloc` symbol. Is that some `-fvisibility=hidden` build?

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