Clang 16 and WebRTC M105

[Ardavon Falls]

Hello all,

Background:
When building WebRTC m105,  when following the instructions provided here (https://webrtc.github.io/webrtc-org/native-code/android/) on the "gclient sync" step, it downloads clang 16 and appears to compile it to be used to compile WebRTC. What is unusual, is that clang 16 isn't released yet and the source for it is being downloaded from an internal google url. Furthermore, we tried to compile with clang 14 (stock tools provided by Apple) on Mac and received errors about usage of these flags which don't exist yet (femit-dwarf-unwind=no-compact-unwind & -Wunqualified-std-cast-call`)

Question(s):
Other than the compiler flags,  is there any reason why google's clang 16 needs to be used? 

Have anyone else used older versions of Clang be used to compile M105?

Thank you

[Byoungchan Lee]

Supporting multiple compilers has a maintenance overhead and Chromium has decided to only use the Tip of Tree clang compiler, and WebRTC follows it.

About a year ago, support for Apple clang was also removed.

For more information see https://webrtc.googlesource.com/src/+/refs/heads/main/g3doc/supported-platforms-and-compilers.md and https://chromium-review.googlesource.com/c/chromium/src/+/3259660 .