Implement BlGetEfiVariable() and BlSetEfiVariable() routines

xtldr/includes/xtldr.h

@@ -137,6 +137,12 @@ EFI_STATUS
 BlGetEfiPath(IN PWCHAR SystemPath,
              OUT PWCHAR *EfiPath);
 
+XTCDECL
+EFI_STATUS
+BlGetEfiVariable(IN PEFI_GUID Vendor,
+                 IN PWCHAR VariableName,
+                 OUT PVOID *VariableValue);
+
 XTCDECL
 VOID
 BlGetMappingsCount(IN PXTBL_PAGE_MAPPING PageMap,
@@ -327,6 +333,13 @@ VOID
 BlSetCursorPosition(IN ULONGLONG PosX,
                     IN ULONGLONG PosY);
 
+XTCDECL
+EFI_STATUS
+BlSetEfiVariable(IN PEFI_GUID Vendor,
+                 IN PWCHAR VariableName,
+                 IN PVOID VariableValue,
+                 IN UINT_PTR Size);
+
 XTCDECL
 EFI_STATUS
 BlShutdownSystem();