Fix Xcode 27 beta build errors

[pblazej]

Summary

Fixes the Xcode 27 beta (macOS 27 / iOS 27 SDK) build failures reported in #1035 and #1037. Behavior is preserved on every OS and toolchain — there is no macOS 12.x regression.

Root cause

These are SDK-side annotation changes that only the Swift importer enforces as hard errors — the underlying APIs still exist on the OS versions they always shipped in:

• Xcode 27 beta build errors (macOS) #1035 — AVAudioNode.auAudioUnit: gained NS_REFINED_FOR_SWIFT; its new Swift overlay is introduced: macOS 13.0, deprecated: 27.0 (in favor of withAUAudioUnit). The Objective-C property is still macos(10.13).
• Xcode 27 beta build errors (macOS) #1035 — SCStreamConfiguration.width/height: re-annotated from the class-inherited macos(12.3) to an explicit macos(13.0) when Apple extended ScreenCaptureKit to iOS/tvOS 27.
• Xcode 27 Beta deprecation error #1037 — RPBroadcastSampleHandler: deprecated in the iOS 27 SDK (ios(10.0, 27.0)). Xcode 27 builds the LKObjCHelpers .pcm with -clang-target …ios27.0, so the deprecation fires and -Werror fails the module. (Requires that clang-target + "treat warnings as errors", which is why it doesn't reproduce on a default build.)

Changes

• Audio (auAudioUnit): new AVAudioNode.maximumFramesToRender extension that centralizes access; call sites (PlayerNodePool, SoundPlayer, MixerEngineObserver) just use node.maximumFramesToRender. It resolves per toolchain/OS:
  • Xcode 26 (compiler < 6.4): the auAudioUnit property directly — unchanged.
  • Xcode 27, OS 27+: withAUAudioUnit { … }, the non-deprecated replacement Apple points to.
  • Xcode 27, macOS 13–26: the auAudioUnit property (available and not yet deprecated there).
  • Xcode 27, below macOS 13: LKObjCHelpers, where the original ObjC availability (macos(10.13)) still applies — so full behavior is preserved with no regression.
• Screen capture (width/height): #if compiler(>=6.4) → LKObjCHelpers.setWidth(…) (Xcode 27, preserves full capture resolution on macOS 12.x); #else → native configuration.width/height (Xcode 26 stays idiomatic).
• Xcode 27 Beta deprecation error #1037: -Wdeprecated-declarations pragma around the finishBroadcastWithoutError: declaration so the precompiled module emits.
• Reverts the macOS exclusion from Exclude macOS from buffer size workaround #1034 (ae0d2fb): maximumFramesToRender matching runs on macOS again via the extension, so the #if os(iOS) || os(visionOS) || os(tvOS) once more wraps only the iOS audio-session logging.
• Build warnings: silenced pre-existing warnings the newer toolchain/SDK surfaces — BroadcastUploader's bare Task { try await … } → Task.discarding; the retroactive AudioStreamBasicDescription: Codable conformance qualified as Swift.Codable (matching the Sendable.swift convention); and kIOMasterPortDefault → guarded kIOMainPortDefault in Utils. The build is now warning-free apart from the unrelated E2EEOptions deprecation.

Note: #if compiler(>=6.4) (toolchain version), not #if swift(>=6.4) (language version) — the latter is false under CocoaPods (swift_versions ["5.9"]) on Xcode 27 and would take the wrong path.

Testing

Built locally against Xcode 27 beta (27A5194q, Swift 6.4) and Xcode 26.5 (Swift 6.3.2):

• Xcode 27: macOS, iOS, tvOS, Mac Catalyst, visionOS — ✅
• Xcode 26.5: macOS, iOS — ✅
• 0 non-deprecation warnings on every platform/toolchain; swiftformat clean

Closes #1035
Closes #1037

🤖 Generated with Claude Code

[pblazej]

It's a little overengineered vs e.g.

if #available(macOS 13.0, *) {
  return auAudioUnit.maximumFramesToRender
}
return LKObjCHelpers.maximumFramesToRender(for: self)

which would surface the deprecation on 27.

[pblazej]

May change in the upcoming betas tho...