[clang-tools-extra] [clang-tidy] Portability Avoid Unprototyped Functions Check (PR #161023)

[via cfe-commits]

isuckatcs wrote:

> So if you have config like this
>
> ```yaml
> # .clang-tidy
> Checks: clang-diagnostic-strict-prototypes
> ExtraArgs: ["-Wstrict-prototypes", "-W...", ...]
> ```

IIUC the `clang-diagnostic-strict-prototypes` check on its own doesn't enable the warning, but what if it did?

I think we could tweak how we handle `clang-diagnostic-<warning>` checks, so `--checks=clang-diagnostic-strict-prototypes` is enough to enable the warning without having to create a `.clang-tidy` file with `ExtraArgs`.

https://github.com/llvm/llvm-project/pull/161023