use khash in equal? impl
use khash in equal? impl

omasanori/picrin,dcurrie/picrin,picrin-scheme/picrin,koba-e964/picrin,ktakashi/picrin,leavesbnw/picrin,koba-e964/picrin,leavesbnw/picrin,ktakashi/picrin,omasanori/picrin,picrin-scheme/picrin,leavesbnw/picrin,ktakashi/picrin,koba-e964/picrin,dcurrie/picrin