adding device selection, buffer creation and pipeline creation to Metal backend

Sources/Backends/Metal/MetalFence.m

@@ -0,0 +1,31 @@
+// Copyright (C) 2025 kanel
+// This file is part of "Pulse"
+// For conditions of distribution and use, see copyright notice in LICENSE
+
+#include <Pulse.h>
+#include "../../PulseInternal.h"
+#include "Metal.h"
+#include "MetalFence.h"
+#include "MetalCommandList.h"
+
+PulseFence MetalCreateFence(PulseDevice device)
+{
+	PulseFence fence = (PulseFence)calloc(1, sizeof(PulseFence));
+	PULSE_CHECK_ALLOCATION_RETVAL(fence, PULSE_NULL_HANDLE);
+	return fence;
+}
+
+void MetalDestroyFence(PulseDevice device, PulseFence fence)
+{
+	free(fence);
+}
+
+bool MetalIsFenceReady(PulseDevice device, PulseFence fence)
+{
+	return true;
+}
+
+bool MetalWaitForFences(PulseDevice device, const PulseFence* fences, uint32_t fences_count, bool wait_for_all)
+{
+	return true;
+}