1921:/lib/library.c (/lib/library.c)
(public int) library_exit_block()
/*
 * Function name: library_exit_block
 * Description:   Returns true if this_player() is in possession of
 *                a book from this library.  It can be used as a block
 *                function for library exits.
 * Returns:       1/0 - library book possessed/not possessed
 */
