Add missing PE subsystem

sdk/xtdk/xtimage.h

@@ -38,6 +38,7 @@
 #define PECOFF_IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER          12
 #define PECOFF_IMAGE_SUBSYSTEM_EFI_ROM                     13
 #define PECOFF_IMAGE_SUBSYSTEM_XBOX                        14
+#define PECOFF_IMAGE_SUBSYSTEM_WINDOWS_BOOT_APPLICATION    16
 #define PECOFF_IMAGE_SUBSYSTEM_XT_NATIVE_APPLICATION       21
 #define PECOFF_IMAGE_SUBSYSTEM_XT_NATIVE_DRIVER            22
 #define PECOFF_IMAGE_SUBSYSTEM_XT_DYNAMIC_LIBRARY          23