Trouble compiling the compiler with sccache and xcodebuild (`cmake -G Xcode`)

Hi all,

I followed the build instructions from GettingStarted.md, up to and including the invocation of utils/build-script, and attempted to take the "sccache-with-Xcode" route, but the resulting xcodebuild invocation invokes clang directly (where instead we want xcodebuild to invoke sccache).

Presumably this is supposed to work, because in GettingStarted, the invocation of build-script that uses --xcode also uses --sccache.

When I use the same invocation of build-script without the --xcode option, everything works fine (and I can see ninja invoking sccache in Activity Monitor).

I'm using xcode version 13A1030d (an RC for 13.1) and macOS 12.0.1 (21A559).

Does anyone else routinely use this combination (--sccache and --xcode)? If so, do you use a setup that differs from the documentation?

I would probably just use the ninja command, except that I get a lot of use out of the code-browsing, completion, & debugging features in xcode, so I want to try to get that working if it's not too hard.

Thanks in advance!