Support for xcframework (macos, ios, tvos, catalyst)

[paulocoutinhox]

Hi,

We need the xcframework for plataforms (macos x64, macos arm64, ios arm64, ios simulator x64 and arm64, tvos simulator and device x64 and arm64, catalyst x64 and arm64)

1. Create a library for each platform and use cmake platform selector to specify the correct library for each:
   https://github.com/leetal/ios-cmake/blob/master/ios.toolchain.cmake#L353-L374

2. Create an IF that check effective platform, example:
   https://github.com/tdlib/td/blob/master/CMake/iOS.cmake#L66-L119

3. Create a xcframework that is a simple command that unify all .a or .so or .dylib files after you use lipo:
   Do a lipo to join all simulators x64 and arm64 into one lib and after, create the xcframework:

xcodebuild -create-xcframework \
  -library ./libxyz_macos.a \
  -headers ./include/ \
  -library ./libxyz_iossimulator.a \
  -headers ./include/ \
  -library ./libxyz_maccatalyst.a \
  -headers ./include/ \
  -library ./libxyz_tvos.a \
  -headers ./include/ \
  -library ./libxyz_ios.a \
  -headers ./include/ \
  -output XYZ.xcframework

Thanks.

[paulocoutinhox]

Thanks!