Revert #225 (d98dc90b38)

Fixes that Windows+SDL builds use the Windows Irrlicht device instead of the SDL Irrlicht device.

source/Irrlicht/CIrrDeviceWin32.h

@@ -4,6 +4,8 @@
 
 #pragma once
 
+#ifdef _IRR_COMPILE_WITH_WINDOWS_DEVICE_
+
 #include "CIrrDeviceStub.h"
 #include "IrrlichtDevice.h"
 
@@ -423,3 +425,5 @@ namespace irr
 	};
 
 } // end namespace irr
+
+#endif // _IRR_COMPILE_WITH_WINDOWS_DEVICE_