[clang] [Clang][Parser] Fix crash of clang when using C++ constructs like :: in C code (PR #74926)

[via cfe-commits]

ChipsSpectre wrote:

@tbaederr The build is fixed now. Can you merge the pull request?

Since I have no write access to llvm-project, it seems I can not do it on my own:

![Screenshot](https://github.com/llvm/llvm-project/assets/11499442/e0fb925f-a72a-4c1e-827f-cb39c99faa4c)


https://github.com/llvm/llvm-project/pull/74926