* agent/agent.h (struct server_control_s): Add field digest.data.
* agent/gpg-agent.c (agent_deinit_default_ctrl): Free that field.
* agent/command.c (reset_notify): Ditto.
(start_command_handler): ditto.
(cmd_sethash): Add new option --inquire.
* agent/call-scd.c (agent_card_pksign): For now return an error if
inquire mode was used.
* agent/command-ssh.c (ssh_handler_sign_request): Make sure
digest.data is cleared.
* agent/divert-scd.c (divert_pksign): Implement inquire mode.
* agent/pksign.c (agent_pksign_do): Ditto.