[BOOT] Add boot manager headers

BOOT/ENVIRON/INC/efilib.h

@@ -0,0 +1,34 @@
+/*++
+
+Copyright (c) 2024, Quinn Stephens.
+Provided under the BSD 3-Clause license.
+
+Module Name:
+
+   efilib.h
+
+Abstract:
+
+    Boot manager EFI library definitions.
+
+--*/
+
+#ifndef _EFILIB_H
+#define _EFILIB_H
+
+#include <nt.h>
+#include "bootmgr.h"
+#include "efi.h"
+
+PBOOT_APPLICATION_PARAMETERS
+EfiInitCreateInputParameters (
+    IN EFI_HANDLE ImageHandle,
+    IN EFI_SYSTEM_TABLE *SystemTable
+    );
+
+EFI_STATUS
+EfiGetEfiStatusCode (
+    IN NTSTATUS Status
+    );
+
+#endif