input_pending
# define input_pending() (nextin!=nextout || \
# define input_pending() bizarre
# define input_pending() rdchk(0)
# define input_pending() bizarre
# define input_pending() (nextin!=nextout || circfill())
# define input_pending() bizarre
# define input_pending() (nextin!=nextout)
# define input_pending() bizarre
# define input_pending() (ioctl(0, FIONREAD, &iocount), \
# define input_pending() bizarre
# define input_pending() rdchk(0)
# define input_pending() bizarre
# define input_pending() (is_input || \
# define input_pending() bizarre
# define input_pending() (false)