rem: keep_new_line (struct buffer_record *b, char *line_start, int line_len)
add: keep_new_line (struct buffer_record *b, char *line_start, size_t line_len)
context: keep_new_line (struct buffer_record *b, char *line_start, int line_len){  struct line *l;  /* If there is no existing area to keep line info, get some. */  if (b->line_start == NULL)    b->line_start = b->curr_line = new_line_control ();  /* If existing area for lines is full, get more. */  if (b->curr_line->used == CTRL_SIZE)    {      b->curr_line->next = new_line_control ();      b->curr_line = b->curr_line->next;    }  l = b->curr_line;  /* Record the start of the line, and update counters. */  l->starts[l->insert_index].str = line_start;  l->starts[l->insert_index].len = line_len;  l->used++;  l->insert_index++;}