[BOOT] Add EFI headers and entry point

BOOT/ENVIRON/INC/ntimage.h

@@ -0,0 +1,26 @@
+/*++
+
+Copyright (c) 2024, the LibreXP developers.
+Provided under the BSD 3-Clause license.
+
+Module Name:
+
+   ntimage.h
+
+Abstract:
+
+   Provides NT image file definitions.
+
+--*/
+
+#ifndef _NTIMAGE_H
+#define _NTIMAGE_H
+
+//
+// Machine type values.
+//
+#define IMAGE_FILE_MACHINE_UNKNOWN 0
+#define IMAGE_FILE_MACHINE_I386    0x014c
+#define IMAGE_FILE_MACHINE_AMD64   0x8664
+
+#endif