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

[Haojian Wu via cfe-commits]

hokein wrote:

Thanks for the prompt response. I think limiting it to C-only will fix the issue (note that there is no `C` in `LangOpts`, you may want to use `!getLangOpts().CPlusPlus` to exclude C++).

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