[BOOT] Add boot manager headers

BOOT/ENVIRON/LIB/EFI/efiinit.c

@@ -0,0 +1,58 @@
+/*++
+
+Copyright (c) 2024, Quinn Stephens.
+Provided under the BSD 3-Clause license.
+
+Module Name:
+
+   efiinit.c
+
+Abstract:
+
+   Provides EFI initialization utilities.
+
+--*/
+
+#include "bootmgr.h"
+#include "efi.h"
+
+UCHAR EfiInitScratch[2048];
+
+PBOOT_APPLICATION_PARAMETERS
+EfiInitCreateInputParameters (
+    IN EFI_HANDLE ImageHandle,
+    IN EFI_SYSTEM_TABLE *SystemTable
+    )
+
+/*++
+
+Routine Description:
+
+    Creates the input parameter structure for the boot application.
+
+Arguments:
+
+    ImageHandle - Handle for the boot manager image.
+
+    SystemTable - Pointer to the EFI system table.
+
+Return Value:
+
+    Pointer to parameter structure on success or NULL on failure.
+
+--*/
+
+{
+    ULONG ScratchUsed = 0;
+    PBOOT_APPLICATION_PARAMETERS InputParameters;
+
+    (VOID)ImageHandle;
+    (VOID)SystemTable;
+
+    InputParameters = (PBOOT_APPLICATION_PARAMETERS)(&EfiInitScratch[ScratchUsed]);
+    InputParameters->Signature = BOOT_APPLICATION_PARAMETERS_SIGNATURE;
+    InputParameters->Version = BOOT_APPLICATION_PARAMETERS_VERSION;
+    ScratchUsed += sizeof(BOOT_APPLICATION_PARAMETERS);
+
+    return InputParameters;
+}

BOOT/ENVIRON/LIB/EFI/efistatus.c

@@ -14,6 +14,7 @@ Abstract:
 --*/
 
 #include "bootmgr.h"
+#include "efi.h"
 
 EFI_STATUS
 EfiGetEfiStatusCode (