Adding SyndiKit

[leogdion]

Pull Request Description

Adding SyndiKit.

Acceptance Criteria

To be accepted into the Swift source compatibility test suite, a project must:

• be an Xcode or swift package manager project
• support building on either Linux or macOS
• target Linux, macOS, or iOS/tvOS/watchOS device
• be contained in a publicly accessible git repository
• maintain a project branch that builds against Swift 4.0 and passes any unit tests
• have maintainers who will commit to resolve issues in a timely manner
• be compatible with the latest GM/Beta versions of Xcode and swiftpm
• add value not already included in the suite
• be licensed with one of the following permissive licenses:
  • BSD
  • MIT
  • Apache License, version 2.0
  • Eclipse Public License
  • Mozilla Public License (MPL) 1.1
  • MPL 2.0
  • CDDL
• pass ./project_precommit_check script run

Ensure project meets all listed requirements before submitting a pull request.

[justice-adams-apple]

@swift-ci test

[justice-adams-apple]

@swift-ci test

[justice-adams-apple]

@leogdion seeing a build failure

/swift-source-compat-suite/project_cache/SyndiKit/.build/checkouts/XMLCoder/Sources/XMLCoder/Encoder/XMLEncoder.swift:26:27: error: static property 'prettyPrinted' is not concurrency-safe because non-'Sendable' type 'XMLEncoder.OutputFormatting' may have shared mutable state [#MutableGlobalVariable]

We'll likely need to update the project to make it work with swift 6.0/6.1 or we can Xfail it within the compat suite

[leogdion]

oder/Encoder/XMLEncoder.swift:26:27: error: static property 'prettyPrinted' is not concurrency-safe because non-'Sendable' type 'XMLEncoder.OutputFormatting' may have shared mutable stat

@leogdion seeing a build failure

/swift-source-compat-suite/project_cache/SyndiKit/.build/checkouts/XMLCoder/Sources/XMLCoder/Encoder/XMLEncoder.swift:26:27: error: static property 'prettyPrinted' is not concurrency-safe because non-'Sendable' type 'XMLEncoder.OutputFormatting' may have shared mutable state [#MutableGlobalVariable]

We'll likely need to update the project to make it work with swift 6.0/6.1 or we can Xfail it within the compat suite

We'll have to XMLCoder or swift-source-compat-suite?

[leogdion]

@justice-adams-apple I forked and fixed XMLCoder and will be using that. It's merged into my branch now.

[justice-adams-apple]

@leogdion 👍 you'll need to update this PR with the new revision of your project in projects.json