message: define pointer to multiboot_info_t as const
  we shouldn't change this pointer
diff: @@ -143,6 +143,6 @@ typedef struct multiboot_mod_list multiboot_module_t;
  /// Pointer to multiboot structure
  /// This pointer is declared at set by entry.asm
  -extern multiboot_info_t* mb_info;
  +extern const multiboot_info_t* const mb_info;
  #endif
  