support '%c' specifier in xfprintf
support '%c' specifier in xfprintf

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