Improved clang type parser target tuple validation

[emesare]

When a user registers the architecture "xtensa" we will attempt to guess the target tuple as "xtensa-unknown-unknown-unknown" which is invalid for our clang build, resulting in any clang parser input failing with:

SyntaxError: error: <unknown>: Unknown error occurred in parsing source.

You can verify this with the type parser:

Screen.Recording.2025-11-25.at.3.53.02.PM.mov

For now if user runs into it they should adjust the type parser arguments in the platform like in windows:

binaryninja-api/platform/windows/platform_windows.cpp

Lines 64 to 82 in 0317c1a

	virtual void AdjustTypeParserInput(
	Ref<TypeParser> parser,
	std::vector<std::string>& arguments,
	std::vector<std::pair<std::string, std::string>>& sourceFiles
	) override
	{
	if (parser->GetName() != "ClangTypeParser")
	{
	return;
	}
	for (auto& arg: arguments)
	{
	if (arg.find("--target=") == 0 && arg.find("-unknown-") != std::string::npos)
	{
	arg = "--target=i386-pc-windows-msvc";
	}
	}
	}