Xcode 14.3 and the macOS 13.3 platform SDK introduced a few breaking
changes:
* Updated AppleClang emits warnings about unqualified std cast calls
when using C++ - as `move` is too broad a word, developers are to use
`std::move` to make this explicit. Alas this is exactly what `json11`
uses and because that library is archived, there is no possibility
of an upstream update.
* Apple guarded calls to old screen capture APIs as "available but
deprecated", but seems to have chosen the wrong lower version
boundary: The calls are flagged as being available for macOS 13 and
macOS 14 only.
To fix this, the existing macOS platform SDK header is replaced by a
local copy that uses macOS 11 as the lower boundary (the oldest macOS
version supported by obs-studio anyway)
