[llvm] [llvm][Support][Windows] Avoid crash calling remove_directories() (PR #118677)

[Martin Storsjö via llvm-commits]

mstorsjo wrote:

Unfortunately, this implementation caused other build issues; it uses `atlbase.h` which is not available in mingw environments at all. (Also within MSVC, ATL is an optional install, even if it quite often is included, and LLVM didn't use to require ATL before either.) So now building for mingw targets is entirely broken.

I guess this affects the use of `CComPtr` here. We don't seem to have all that much COM code within LLVM so far, but we have `llvm/include/llvm/Support/COM.h` with the `InitializeCOMRAII` wrapper for the COM init itself.

Is it possible to write a similar COM pointer wrapper that we can use, instead of relying on ATL for this? Covering the uses we have here should be quite trivial I guess?

https://github.com/llvm/llvm-project/pull/118677