[Core] Added POSIX support (Experimental)

Thanks to Danman
I don't think it actually compile although tried my best to correct
code.


Former-commit-id: c3366c2c924f7392f4d46824dafca63ecf7f1fea

src/Nazara/Core/Posix/ClockImpl.cpp

@@ -0,0 +1,28 @@
+// Copyright (C) 2012 Alexandre Janniaux
+// This file is part of the "Nazara Engine - Core module"
+// For conditions of distribution and use, see copyright notice in Config.hpp
+
+#include <Nazara/Core/Posix/ClockImpl.hpp>
+#include <Nazara/Core/Error.hpp>
+#include <ctime>
+#include <sys/time.h>
+#include <Nazara/Core/Debug.hpp>
+
+bool NzClockImplInitializeHighPrecision()
+{
+	return true; // No initialization needed
+}
+
+nzUInt64 NzClockImplGetMicroseconds()
+{
+	timeval clock;
+	gettimeofday(&clock, nullptr);
+	return static_cast<nzUInt64>(clock.tv_sec*1000000 + (clock.tv_nsec/1000));
+}
+
+nzUInt64 NzClockImplGetMilliseconds()
+{
+	timeval clock;
+	gettimeofday(&clock, nullptr);
+	return static_cast<nzUInt64>(clock.tv_sec*1000 + (clock.tv_nsec/1000000));
+}