[llvm] [Support] Handle delete_pending case for Windows fs::status (PR #90655)

[Jeremy Day via llvm-commits]

z2oh wrote:

Looking into this; they are using clang to compile (instead of clang-cl) and so CMake's MSVC var is false, failing [this condition](https://github.com/z2oh/llvm-project/blob/078ba3cea20bc91a60c9daa07df764d72dfd282e/llvm/lib/Support/CMakeLists.txt#L40), and not adding ntdll as a system lib. I'm trying to figure out now where else this lib can be specified to support building under this configuration.

https://github.com/llvm/llvm-project/pull/90655