Migrate Unity iOS/macOS native integration

[melekr]

Changes summary

This PR migrates the Unity native integration from the legacy cocoa static libraries to dynamic backtrace-cocoa frameworks:

• iOS: link Backtrace.xcframework (dynamic) + CrashReporter.xcframework (static), embed Backtrace, set Swift/platform flags via a post-build.
• macOS: Update plugin bundle (BacktraceMacUnity.bundle) that exports the native C API and nests Backtrace.framework for runtime. PLCrashReporter is linked statically.

The public C# API remains unchanged, only NativeClient and build steps are updated.

Why this change

• Modern packaging: XCFramework is Apple’s native distribution format for binary SDKs. Bundles device & simulator slices + correct slice selection at build time and Privacy & resources packaging.
• Stability/maintainability: Native standard Apple linking/embedding semantics + Swift runtime embedding of Swift stdlibs.
• Parity: aligns Unity integration with Backtrace’s official iOS/macOS SDK expectations.

Footprint

Sample Reports

What's next

• Expose more cocoa settings & expand configuration
• Offload/remove frameworks and bundle from repo

[konraddysput]

bad formatting

[konraddysput]

Small nit:

what do you think about?

Suggested change

	#if UNITY_2019_3_OR_NEWER
	string appTargetGuid = project.GetUnityMainTargetGuid();
	string unityFrameworkTargetGuid = project.GetUnityFrameworkTargetGuid();
	#else
	string appTargetGuid = project.TargetGuidByName("Unity-iPhone");
	string unityFrameworkTargetGuid = appTargetGuid;
	#endif
	string appTargetGuid =
	#if UNITY_2019_3_OR_NEWER
	project.GetUnityMainTargetGuid();
	#else
	project.TargetGuidByName("Unity-iPhone");
	#endif
	string unityFrameworkTargetGuid =
	#if UNITY_2019_3_OR_NEWER
	project.GetUnityFrameworkTargetGuid();
	#else
	appTargetGuid;
	#endif

[konraddysput]

can we move it to class instance? It's not popular in C# to have a function declaration inside another function. its also inconsistent with the rest of the library code

[konraddysput]

small nit:

Suggested change

	var backtraceXCPath = FindXCFramework("Backtrace.xcframework");
	var crashReporterXCPath = FindXCFramework("CrashReporter.xcframework");
	if (string.IsNullOrEmpty(backtraceXCPath))
	{
	Debug.LogError($"[Backtrace] Could not locate Backtrace.xcframework under: {buildPath}");
	return;
	}
	if (string.IsNullOrEmpty(crashReporterXCPath))
	{
	Debug.LogError($"[Backtrace] Could not locate CrashReporter.xcframework under: {buildPath}");
	return;
	}
	var backtraceXCPath = FindXCFramework("Backtrace.xcframework");
	if (string.IsNullOrEmpty(backtraceXCPath))
	{
	Debug.LogError($"[Backtrace] Could not locate Backtrace.xcframework under: {buildPath}");
	return;
	}
	var crashReporterXCPath = FindXCFramework("CrashReporter.xcframework");
	if (string.IsNullOrEmpty(crashReporterXCPath))
	{
	Debug.LogError($"[Backtrace] Could not locate CrashReporter.xcframework under: {buildPath}");
	return;
	}

[konraddysput]

small nit:

Suggested change

	string relCrashReporterXC = ToProjectRelative(buildPath, crashReporterXCPath);
	// Add file references
	string backtraceFileGuid = project.FindFileGuidByProjectPath(relBacktraceXC);
	if (string.IsNullOrEmpty(backtraceFileGuid)) {
	backtraceFileGuid = project.AddFile(relBacktraceXC, relBacktraceXC, PBXSourceTree.Source);
	}
	string crashReporterFileGuid = project.FindFileGuidByProjectPath(relCrashReporterXC);
	if (string.IsNullOrEmpty(crashReporterFileGuid)) {
	crashReporterFileGuid = project.AddFile(relCrashReporterXC, relCrashReporterXC, PBXSourceTree.Source);
	}
	// Add file references
	var backtraceFileGuid = project.FindFileGuidByProjectPath(relBacktraceXC);
	if (string.IsNullOrEmpty(backtraceFileGuid)) {
	backtraceFileGuid = project.AddFile(relBacktraceXC, relBacktraceXC, PBXSourceTree.Source);
	}
	var relCrashReporterXC = ToProjectRelative(buildPath, crashReporterXCPath);
	var crashReporterFileGuid = project.FindFileGuidByProjectPath(relCrashReporterXC);
	if (string.IsNullOrEmpty(crashReporterFileGuid)) {
	crashReporterFileGuid = project.AddFile(relCrashReporterXC, relCrashReporterXC, PBXSourceTree.Source);
	}