Split libnu into libplatform, libamex

Going to add some ALLS stuff to libplatform and the ALLS hardware
does not contain an AMEX board.

amex/ds.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <windows.h>
+
+DEFINE_GUID(
+        ds_guid,
+        0x279A9F67,
+        0x348F,
+        0x41C9,
+        0xA4, 0xC4, 0xDF, 0xDB, 0x8A, 0xE8, 0xE5, 0xE0);
+
+HRESULT ds_hook_init(void);