Rationale: we are using Swift compiler as a library in a downstream project and having these exposed would streamline version detection for our use case.
Additionally, this PR makes CMake config a bit more uniform with LLVM/Clang configs.
These changes caused a number of issues:
1. No debug info is emitted when a release-debug info compiler is built.
2. OS X deployment target specification is broken.
3. Swift options were broken without any attempt any recreating that
functionality. The specific option in question is --force-optimized-typechecker.
Such refactorings should be done in a fashion that does not break existing
users and use cases.
This reverts commit e6ce2ff388.
This reverts commit e8645f3750.
This reverts commit 89b038ea7e.
This reverts commit 497cac64d9.
This reverts commit 953ad094da.
This reverts commit e096d1c033.
rdar://30549345
Expanding this at include time doesn't work correctly for LLDB because the variable conventions aren't consistent. Expanding and configure time means the Swift variables get expanded and passed along.
Since Swift's build tree configuration depends on CMark, we should also include the CMark targets if they are not present and the Exports file is available.
This patch generates SwiftExports.cmake and SwiftConfig.cmake in the build tree to be compatible with CMake's `find_package` function for importing targets between CMake build trees. This will allow LLDB to consume Swift's targets and infer their transitive dependencies.
