private key format/convert to standard OpenSSL format

[Reza Curtmola]

Is there a way to convert an RSA private key generated with
'dnssec-keygen' into a DER/PEM encoded key that is recognized by OpenSSL ?
(e.g. using header and footer lines
-----BEGIN RSA PRIVATE KEY-----
-----END RSA PRIVATE KEY-----)

The only way I can think of is to use the BIND library to read the private
key from a file into a structure and then use the OpenSSL library to save
it PEM encoded into another file.

Is there an easier way to do this?