- Switch to C++11 steady clock

- Move the C++11 implementation to d_main
- Remove the platform specific timer implementations

src/g_level.cpp

@@ -94,6 +94,7 @@
 #include "g_levellocals.h"
 #include "actorinlines.h"
 #include "vm.h"
+#include "d_main.h"
 
 #include <string.h>
 
@@ -1020,7 +1021,7 @@ void G_DoLoadLevel (int position, bool autosave)
 
 		if (firstTime)
 		{
-			starttime = I_GetTime (false);
+			starttime = I_GetTime ();
 			firstTime = false;
 		}
 	}