secdtool.scm: (free-variables), (bound-variables)

0) repl.scm: (for-each), (list-fold), (vector-map);
1) hashtable.scm:
    (hashtable-mb-ref), (hashtable-exists?), (alist->hashtable),
    (hashtable-merge!), (hashtable-fold), (hashtable-keys),
    (hashtable-copy);
2) secdtool.scm:
    (free-variables func), (bound-variables func)