[llvm-branch-commits] [clang] [clang][driver][clang-cl] Fix unused argument warning for `/std:c++20` for precompiled module inputs to `clang-cl` (PR #102438)

[Tobias Hieta via llvm-branch-commits]

tru wrote:

This PR is pretty messy: Several commits instead of a single that can be cherry-picked, merge commit that makes it harder to cherry-pick and squash.

Please update the PR to contain a single commit that fixes the issue and doesn't contain any merge commits, then I can merge it easily.

Thanks.

https://github.com/llvm/llvm-project/pull/102438