Support Macros on Windows

[compnerd]

Investigating issues with enabling Macros on Windows:

• CI build support for extracting the toolchain
• build issues (references to early build)
• memory corruption
• array truncations
• fix ASTGen
• fix swift-frontend
• fix swift-driver
• fix tests for Windows
• Update packaging to include the new content

Change Set:

• LLVMSupport: partially backport 6613f4aff85b24a13d4f5f7e9cd24bf3f44037a3 llvm-project#7377
• build: adjust the build to wire up the library search path llvm-project#7378
• build: set the CMAKE_RUNTIME_OUTPUT_DIRECTORY swift-syntax#2130
• build: adjust the build to support non-Apple environments #68258
• build: clean up dependency tracking for portability #68256
• build: quote possibly empty parameters #68257
• swift-plugin-server: adjust API for portability #68268
• [Macros/C bridging] Replace use of free for Swift-allocated pointer #68271
• [Swift bridging] Consistently use correctly-defined Swift(U)Int for bridging #68278
• AST,Basic: update support for process execution on Windows #68280
• ASTGen: account for alternate path separators #68291
• SourceKit: handle Windows paths for request options #68292
• tests: replace shell with python for portability #68302
• tests: add missing env #68307
• tests: remove gratuitous use of tee #68308
• test: introduce a new %swift-plugin-dir macro #68309
• test: mark a job incompatible with Swift parser #68313
• test: loosen expectations to support Windows #68314
• test: sink -no-toolchain-stdlib-rpath into lit #68315
• test: introduce a helper for building mock plugins #68318
• utils: update the build-windows-toolchain.bat to extract the toolchain #68319
• Update windows-link-job.swift #68321
• Driver: virtualise the plugin path handling #68322
• ASTGen: add a workaround for CSC conformance visibility #68323
• SwiftDriver: speculative changes to support Windows macros swift-driver#1433
• WiX: package up macro support libraries swift-installer-scripts#245

[compnerd]

State of the world:

• 2 test failures:
  • requires changes to swift-driver & swift-driver for the default plugin directory
  • CustomStringConvertible conformance is not being seen resulting in the error message being rendered improperly
• Update the CI build script to invoke the build appropriately
• Need to fix the build system to wire together the toolchain.
• Update the packaging rules

[compnerd]

5.9.1 is out with the support.