message: Add lifetimebound to attributes for general-purpose usage
diff: # endif
  #endif
  +#if defined(__clang__)
  +# if __has_attribute(lifetimebound)
  +# define LIFETIMEBOUND [[clang::lifetimebound]]
  +# else
  +# define LIFETIMEBOUND
  +# endif
  +#else
  +# define LIFETIMEBOUND
  +#endif
  +
  #endif // BITCOIN_ATTRIBUTES_H
  