rem: fail = buf_init_from_stdin (&x, eol_byte); if (fail)
add: if (! buf_init_from_stdin (&x, eol_byte))
context: tac_mem (){  Buf x;  Line_ptr bol;  char eol_byte = '\n';  int fail;  fail = buf_init_from_stdin (&x, eol_byte);  if (fail)    {      buf_free (&x);      return 1;    }  /* Special case the empty file.  */  if (EMPTY (&x))    return 0;  /* Initially, point at one past the last byte of the file.  */  bol.i = x.n_bufs - 1;  bol.ptr = ONE_PAST_END (&x, bol.i);  while (1)    {      Line_ptr new_bol;      int found = find_bol (&x, &bol, &new_bol, eol_byte);      if (!found)	break;      print_line (stdout, &x, &new_bol, &bol);      bol = new_bol;    }  return 0;}