Xcode: Inherit Swift flags and compilation conditions

Extend the change from commit dfaf55fbfd (Xcode: add extra
'$(inherited)' entries using InheritBuildSettingAttribute, 2021-05-03,
v3.21.0-rc1~182^2) to cover Swift flags and compilation conditions,
allowing CocoaPods and CMake to interoperate when used in the same
project.
5 files changed