(In reply to Ted Mielczarek [:ted] [:ted.mielczarek] from comment #1)
I don't think we can install an arbitrary version of a macOS SDK in an automated way unfortunately. SDKs ship as part of XCode, and I don't believe the license allows for redistribution.
I think that's correct, but https://github.com/phracker/MacOSX-SDKs/releases is playing fast and loose with those rules. I'm not concerned about enabling this potential infringement via glue code in