fix segv in is_quote etc
fix segv in is_quote etc

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