rem: column = column + 8 - column % 8;
add: column += TAB_WIDTH - column % TAB_WIDTH;
context: adjust_column (int column, char c){  if (!count_bytes)    {      if (c == '\b')	{	  if (column > 0)	    column--;	}      else if (c == '\r')	column = 0;      else if (c == '\t')	column = column + 8 - column % 8;      else /* if (isprint (c)) */	column++;    }  else    column++;  return column;}