* g10/pkglue.h (sexp_extract_param_sos): New.
* g10/build-packet.c (sos_write): New.
(do_key, do_pubkey_enc, do_signature): Use sos_write for ECC.
* g10/export.c (cleartext_secret_key_to_openpgp): Use
sexp_extract_param_sos.
(transfer_format_to_openpgp): Use opaque MPI for ECC.
* g10/keygen.c (ecckey_from_sexp): Use sexp_extract_param_sos.
* g10/keyid.c (hash_public_key): Handle opaque MPI for SOS.
* g10/parse-packet.c (sos_read): New.
(parse_pubkeyenc,parse_signature,parse_key): Use sos_read for ECC.
* g10/pkglue.c (sexp_extract_param_sos): New.
(pk_verify): Handle opaque MPI for SOS.
(pk_encrypt): Use sexp_extract_param_sos.
* g10/seskey.c (encode_session_key): Use opaque MPI.
* g10/sign.c (do_sign): Use sexp_extract_param_sos.