This change introduces a new compilation target platform to the Swift compiler - visionOS.
- Changes to the compiler build infrastrucuture to support building compiler-adjacent artifacts and test suites for the new target.
- Addition of the new platform kind definition.
- Support for the new platform in language constructs such as compile-time availability annotations or runtime OS version queries.
- Utilities to read out Darwin platform SDK info containing platform mapping data.
- Utilities to support re-mapping availability annotations from iOS to visionOS (e.g. 'updateIntroducedPlatformForFallback', 'updateDeprecatedPlatformForFallback', 'updateObsoletedPlatformForFallback').
- Additional tests exercising platform-specific availability handling and availability re-mapping fallback code-path.
- Changes to existing test suite to accomodate the new platform.
We didn't have a consistent way to utter attributes in diagnostics, sometimes saying the
'foo' attribute is not allowed
@foo attribute is not allowed
'foo' is not allowed
@foo is not allowed
etc. Standardize on the last one, since it is clear (with the @ sign, with no quotes, with no
'attribute' word in the diagnostic) that we're talking about an attribute. Move a bunch of
diagnostics inline with this.
Swift SVN r25524
