# define _XBT_GNUC_FORMAT( arg_idx ) \
__attribute__((__format_arg__ (arg_idx)))
# define _XBT_GNUC_NORETURN __attribute__((__noreturn__))
+# define _XBT_GNUC_UNUSED __attribute__((unused))
#else /* !__GNUC__ */
# define _XBT_GNUC_PRINTF( format_idx, arg_idx )
# define _XBT_GNUC_SCANF( format_idx, arg_idx )
# define _XBT_GNUC_FORMAT( arg_idx )
# define _XBT_GNUC_NORETURN
+# define _XBT_GNUC_UNUSED
#endif /* !__GNUC__ */