[Question] Does `clangd-indexer` support `-vfsoverlay`?

Hello,

I am trying to find out if I can build the index daily on CI machines. And our code uses `-vfsoverlay` in order to emulate some header maps and Darwin framework structure for `clangd` and `clang-tidy`. But, it doesn't seem to work with `clangd-indexer`. The `compile_commands.json` already contains `--vfsoverlay` flag and the command itself compiles well.

Do I supply the `--vfsoverlay` differently similar to `clang-tidy`?

I guess, I have a question related to this somehow: https://github.com/llvm/llvm-project/issues/159843

Seems like, it's coming to more interesting question: Do we support VFS cohesively across LLVM tools? Or we better not to use it at all?

Thank you.

Start by reproducing the clangd-indexer invocation with the existing compile_commands.json and its --vfsoverlay flag. Compare how clangd-indexer and clang-tidy handle VFS overlays, then use the related LLVM issue for context. Done means the supported invocation or an implementation gap is clearly established and documented or addressed.

Written by the indexing model from the issue text.