predef_charsets_mutex  843 src/char.c     static ScmInternalMutex predef_charsets_mutex;
predef_charsets_mutex  849 src/char.c         SCM_INTERNAL_MUTEX_LOCK(predef_charsets_mutex);
predef_charsets_mutex  876 src/char.c         SCM_INTERNAL_MUTEX_UNLOCK(predef_charsets_mutex);
predef_charsets_mutex  891 src/char.c         SCM_INTERNAL_MUTEX_INIT(predef_charsets_mutex);