[bugfix] write-string doesn't detect given port
[bugfix] write-string doesn't detect given port

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