[clang] [Clang][Sema] Allow counted_by on void* in GNU mode (PR #164737)

[Yeoul Na via cfe-commits]

rapidsna wrote:

> Weirdly, I think a mismatched diagnostic string would be much more well tolerated by the Linux dev community. :) That kind of thing I can document along with the __counted_by macro. If others prefer this route, I can update the PR to do this instead?

What do you mean by "a mismatched diagnostic string" here?

https://github.com/llvm/llvm-project/pull/164737