* scd/app-openpgp.c (CURVE_SEC_P256K1, get_algo_byte): New.
(store_fpr): Support ECC keys with varargs.
(get_ecc_key_parameters, get_curve_name): Support secp256k1.
(parse_ecc_curve): Likewise.
(build_ecdsa_privkey_template, rsa_writekey, ecdsa_writekey): New.
(ecdh_writekey): New.  Not implemented yet.
(do_writekey): Call rsa_writekey, ecdsa_writekey, or ecdh_writekey.
(do_genkey): Follow the change of store_fpr.