[clang] [clang][MBD] set up module build daemon infrastructure (PR #67562)

[Michael Spencer via cfe-commits]

Bigcheese wrote:

> I had a couple of questions. I guess my main concern here is that the TODO for portability might turn out to be quite heavy lifting. Perhaps we should be looking to abstract the socket-like interface at a lower level.

We have someone working on a simple socket library for LLVM support that can handle the portability issues, plan is to land that first.

https://github.com/llvm/llvm-project/pull/67562