Implemented CMake methods for:
* Deleting the old headers before generating the new headers.
* Updating the "Developer" and "framework-include" headers.
* Generating the private frameworks headers into their proper dedicated folders ("PrivateFrameworks" and "framework-private-include")
Updated multiple frameworks to take advantage of this feature.
* Fix the Carbon framework to properly reexport the right frameworks
* Add many missing Carbon-related type definitions
* A couple of fixes in some submodules (see their commits)
[skip ci]
Skipping CI because I know the build is currently broken with this commit; I'm going to revert our use of mDNSResponder and add back our libsystem_dnssd stub, and then patch up libresolv/libinfo to fix DNS resolution (if necessary)
The public headers are imported from the macOS SDK and from the last released OpenDirectory (version 146); it's ok to import them from the SDK because they're still APSL licensed
[skip ci]
Also symlink framework header directories directly into the SDK frameworks. The headers are contained in their own namespace directory, so it doesn't matter if private headers are visible
Also prune unnecessary symlinks to directories that *should* be in the SDK include directory now
