[clang] [clang-repl] Extend the C support. (PR #89804)

[Haojian Wu via cfe-commits]

hokein wrote:

> I want to somehow record this breakage in the form of a test for our future selves when decide to revisit this workaround-looking code.

This is the processed file  https://gist.github.com/hokein/e4a5881329c3956494afa2de7d350476.

> I am a bit overwhelmed right now, are you willing to open a PR with that change so we can merge it -- otherwise I could look later this week :(

Sure, I will prepare one.

https://github.com/llvm/llvm-project/pull/89804