How to do error handling for PInvoke calls

[Louis9902]

Hey together, I got the following small program and I want to compile it as small as possible. So I tried to use the following command bflat build -o program --os windows --arch arm64 --no-reflection --no-stacktrace-data --no-globalization --no-exception-messages -Os --no-pie --separate-symbols --stdlib Zero. As you can see, I want to use the Zero stdlib because the program does not use any of the fancy stuff from the stdlib.
But when compiling the program, I noticed some problems regarding the external calls. One of them is the fact that the DllImport from the Zero lib does not support the SetLastError property. I don't know if that's by design or not.
The second thing is I am apparently not able to get the last global error set by the runtime. With the normal stdlib I would use Marshal.GetLastWin32Error or Marshal.GetLastPInvokeError, but both of these are not available in the zero stdlib. So my question is how should I go about this, because I'm not that deep into native interop with C#

internal static class Interop
{
	public delegate bool ConsoleCtrlDelegate(uint dwCtrlEvent);

	[DllImport("kernel32.dll", SetLastError = true)]
	public static extern bool FreeConsole();

	[DllImport("kernel32.dll", SetLastError = true)]
	public static extern bool AttachConsole(uint dwProcessId);

	[DllImport("kernel32.dll", SetLastError = true)]
	public static extern bool SetConsoleCtrlHandler(ConsoleCtrlDelegate? handlerRoutine, bool add);

	[DllImport("kernel32.dll", SetLastError = true)]
	public static extern bool GenerateConsoleCtrlEvent(uint dwCtrlEvent, uint dwProcessGroupId);
}

internal static class Program
{
	public static int Main(string[] args)
	{
		var processId = uint.Parse(args[0], CultureInfo.InvariantCulture);
		var signal = uint.Parse(args[1], CultureInfo.InvariantCulture);

		// detach from the current console, if one is attached to the process.
		Interop.FreeConsole();

		var success =
			// attach to the target process group
			Interop.AttachConsole(processId) &&
			// set to ignore signals on self, so the proper exit code can be return
			Interop.SetConsoleCtrlHandler(null, true) &&
			// send the signal to the process group
			Interop.GenerateConsoleCtrlEvent(signal, 0);

		return success ? 0 : Marshal.GetLastPInvokeError();
	}
}