Add gettimeofday() syscall and LibC wrappers gettimeofday() and time().

This only has second accuracy right now, I'll work out subseconds later.

Kernel/RTC.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include "types.h"
+
+namespace RTC {
+
+void initialize();
+time_t now();
+time_t bootTime();
+
+}
+