[SDK] Big update

Signed-off-by: Quinn Stephens <quinn@osmora.org>

SDK/INC/CRT/stdarg.h

@@ -1,6 +1,6 @@
 /*++
 
-Copyright (c) 2024, Quinn Stephens.
+Copyright (c) 2024-2025, Quinn Stephens.
 Provided under the BSD 3-Clause license.
 
 Module Name:
@@ -9,14 +9,14 @@ Module Name:
 
 Abstract:
 
-   Provides variable arguments definitions.
+   Provides variable argument list definitions.
 
 --*/
 
 #pragma once
 
 #ifndef _STDARG_H
-#define _STDARG_H
+#define _STDARG_H 1
 
 #ifdef __cplusplus
 extern "C" {