[clang] [llvm] Convert clang-format to Opt and add multicall support (PR #201730)

[via cfe-commits]

mydeveloperday wrote:

If the reason for using this is to use multicall driver, I don't and can't imagine I'll every personally care about that. I don't see why we need a much more complex mechanism for defining options just to do this.. I don't know what is wrong with the existing code which means it can't me made to work, but this doesn't feel like a good change for the good of clang-format to me, and personally I don't have any skin in the game outside of clang-format. Sorry I'd need more convincing before giving this a "yes from me" for us here.

https://github.com/llvm/llvm-project/pull/201730