- Remove code signing requirements for non-macOS
- Do not set deployment target for non-macOS
- Build static library for compiler feature detection for non-macOS
- Use framework to run CompilerId tests for watchOS
- Port tests to new SDK handling
- Add new Apple cross-compiling section to toolchain documentation
Closes: #17870
Currently the CMAKE_XCODE_EFFECTIVE_PLATFORMS property acts only as
a kind of toggle switch to enable iOS project layout features.
But instead of relying on this undocumented property, better detect
the presence of an iOS SDK directly.