Fixes missing CoreFoundation declarations since bump to 3.19.3,
e.g. `error: unknown type name 'CFUUIDRef'`
ApplicationServices.h transitively includes CoreFoundation.h, but as we
patch ApplicationServices out of CMake, the CF symbols were not visible.
Previously this was not a concern, as they were not needed until
https://github.com/Kitware/CMake/commit/d250b67722abcfe1bcd22511943f3e032ef1ef3d
cf-private is not necessary here. cmake just needs the CoreFoundation
framework to be used. swift-corefoundation seems to work fine in this case.
/cc @lnl7
Ryan Burns