Merged requested to merge brad.king/cmake:xcode-swift-defs into master
Xcode has a separate setting for Swift compile definitions, so we can compute a dedicated value for it. Therefore we can:
Support the COMPILE_LANGUAGE generator expression for Swift-specific filters.
Avoid passing the
=valuepart of definitions, which Swift does not support.
This revises !7388 (merged) and reverts commit 12c6fec6, as the latter is no longer needed.
Fixes: #24086 (closed)