[clang] [llvm] [LLVM] Infer compression format from zlib and zstd headers (PR #222773)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

@jh7370 updated the stack to use this approach. I elected to keep the magic detection private to the implementation and just expose routines that take a raw byte stream instead.

https://github.com/llvm/llvm-project/pull/222773