[BOOT] Add EFI headers and entry point

BOOT/ENVIRON/INC/AMD64/efibind.h

@@ -0,0 +1,76 @@
+/*++
+
+Copyright (c) 2024, the LibreXP developers.
+Provided under the BSD 3-Clause license.
+
+Module Name:
+
+   efibind.h
+
+Abstract:
+
+   Provides definitions specific to AMD64 EFI systems.
+
+--*/
+
+#if defined(_MSC_EXTENSIONS)
+    typedef unsigned __int64 uint64_t;
+    typedef __int64 int64_t;
+    typedef unsigned __int32 uint32_t;
+    typedef __int32 int32_t;
+    typedef unsigned __int16 uint16_t;
+    typedef __int16 int16_t;
+    typedef unsigned __int8 uint8_t;
+    typedef __int8 int8_t;
+#elif defined(UNIX_LP64)
+    typedef unsigned long uint64_t;
+    typedef long int64_t;
+    typedef unsigned int uint32_t;
+    typedef int int32_t;
+    typedef unsigned short uint16_t;
+    typedef short int16_t;
+    typedef unsigned char uint8_t;
+    typedef char int8_t;
+#else
+    typedef unsigned long long uint64_t;
+    typedef long long int64_t;
+    typedef unsigned int uint32_t;
+    typedef int int32_t;
+    typedef unsigned short uint16_t;
+    typedef short int16_t;
+    typedef unsigned char uint8_t;
+    typedef char int8_t;
+#endif
+
+typedef uint64_t UINT64;
+typedef int64_t INT64;
+typedef uint32_t UINT32;
+typedef int32_t INT32;
+typedef uint16_t UINT16;
+typedef int16_t INT16;
+typedef uint8_t UINT8;
+typedef int8_t INT8;
+
+typedef int64_t INTN;
+typedef uint64_t UINTN;
+
+#define EFI_ERROR_MASK     0x8000000000000000
+#define EFI_ERROR_MASK_OEM 0xc000000000000000
+#define EFIERR(e)     (EFI_ERROR_MASK | e)
+#define EFIERR_OEM(e) (EFI_ERROR_MASK_OEM | e)
+
+#ifndef EFIAPI
+#if defined(_MSC_EXTENSIONS)
+    #define EFIAPI __cdecl
+#else
+    #define EFIAPI __attribute__((ms_abi))
+#endif
+#endif
+
+#define VOLATILE volatile
+
+#if defined(__GNUC__) || defined(_MSC_EXTENSIONS)
+#define INTERFACE_DECL(n) struct n
+#else
+#define INTERFACE_DECL(n) typedef struct n
+#endif