[CMakeToolchain] Adding Xcode flags

[franramirez688]

Changelog: Feature: Added new configuration fields: tools.apple:enable_bitcode, tools.apple:enable_arc and tools.apple:enable_visibility.
Changelog: Feature: Added new mechanism to inject common Xcode flags in CMakeToolchain generator if enabled Bitcode, ARC, or Visibility configurations.
Closes: #9448
Docs: conan-io/docs#2506

[franramirez688]

Basically, what I'm trying to do is to add some capabilities from the https://github.com/leetal/ios-cmake repository so we'll be able to add some common Xcode flags if those configurations are enabled/disabled.

[lasote]

I have to check the toolchain you used as a reference to understand a little bit but at first sight, this looks good.

[memsharded]

Please have a look at the comments

[MarkusWittlinger]

Hi @franramirez688 ,
I have a quick question (and I hope it is OK to comment here).
Is there a reason why the VISIBILITY is not passed to the CONAN_C_FLAGS but only to the C++ ones?

I had a look at the ios-cmake repo and there it is set for both CMAKE_C_FLAGS and CMAKE_CXX_FLAGS (see https://github.com/leetal/ios-cmake/blob/master/ios.toolchain.cmake).

[franramirez688]

Hi @franramirez688 , I have a quick question (and I hope it is OK to comment here). Is there a reason why the VISIBILITY is not passed to the CONAN_C_FLAGS but only to the C++ ones?

I had a look at the ios-cmake repo and there it is set for both CMAKE_C_FLAGS and CMAKE_CXX_FLAGS (see https://github.com/leetal/ios-cmake/blob/master/ios.toolchain.cmake).

That's a very good question. It looks like a bug indeed 🤔 I don't remember why but it looks like it was missed...