[llvm] Fixed Windows build warnings (PR #68978)

[Nikita Popov via llvm-commits]

nikic wrote:

> @nikic, sorry to bother you(I just saw you in the owners file), could you tell me how to request a review for PR? I couldn't find a description [here](https://llvm.org/docs/GitHub.html#github-reviews). And I don't have a button for adding reviewers..

Unfortunately, non-members can't request reviews. And due to a known bug (https://github.com/llvm/llvm-project/issues/68748) the subscriber emails also don't get sent in this case right now. I've approved the workflow run now, so hopefully one of the subscribers picks this up.

https://github.com/llvm/llvm-project/pull/68978