[clang] [clang] Support --sysroot= for ${arch}-windows-msvc targets (PR #96417)

[via cfe-commits]

trcrsired wrote:

> Just because the PR has been up for a long time isn't a reason for cutting the discussion short - especially for something that defines new public interfaces in how Clang interacts with other toolchain components.

Feel free to have more discussions. But something like how talking about POSIX style sysroot being not the de facto standard and even llvm itself is packaged this way really leads the discussions to nowhere. It is not constructive, it does not contribute to help on i should do. I am the one who does the real hard work and it is a painfull infinite grind for me giving the fact i do not even have a job to feed myself.

Case insensitive is something i strongly oppose mainly for it is known to be implemented very buggy and often security flaws. And there are code out there (like linux kernel headers i shown here) use different filenames but with same case insensitive filenames.

https://github.com/llvm/llvm-project/pull/96417