support environments without libedit
support environments without libedit

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