SCM_CLASS_CHARSET  252 src/char.c         SCM_SET_CLASS(cs, SCM_CLASS_CHARSET);
SCM_CLASS_CHARSET 2991 src/class.c        CINIT(SCM_CLASS_CHARSET,          "<char-set>");
SCM_CLASS_CHARSET  896 src/gauche.h   #define SCM_CHARSETP(obj)  SCM_XTYPEP(obj, SCM_CLASS_CHARSET)