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

[Vassil Vassilev via cfe-commits]

vgvassilev 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++).

Makes sense. If that works for you, we can check this in. 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.

Out of curiosity, in what context you use `-fincremental-extensions`?

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