Profiling: measure time on POSIX systems using clock_gettime

Source/Core/Common/PerformanceCounter.h

@@ -0,0 +1,17 @@
+// Copyright 2014 Dolphin Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#pragma once
+
+#if !defined(_WIN32)
+
+#include <cstdint>
+
+#include "Common/CommonTypes.h"
+
+typedef u64 LARGE_INTEGER;
+bool QueryPerformanceCounter(u64* out);
+bool QueryPerformanceFrequency(u64* lpFrequency);
+
+#endif