CMake support for Xcode,

Implements toolchain for CMake (CeeMake),
which supports iOS (EyeOhEss), Mac's Catalyst and MacOS targets fully,
but tvOS and watchOS targets should work as well (I mean, just not tested).

cmake-ios-toolchain

Let's appreciate that the example demonstrates running CMake directly from Xcode
(and this does not just add iOS support into CMake).

Why?

Because even in 2021, CMake still does not have built-in support.

Also, I just did NOT want to use CMake's generate-project feature (and then modify result into iOS version). Basically, that would break the whole point of using CMake in the first place! (which was editing a single script to update all platforms).