* scdaemon.c, scdaemon.h: New option --disable-opensc.
* card.c (card_open): Implement it.
* apdu.c (open_osc_reader, osc_send_apdu): New.
(apdu_open_reader) [HAVE_OPENSC]: Use the opensc driver if not
disabled.
(error_string) [HAVE_OPENSC]: Use sc_strerror.
(send_apdu) [HAVE_OPENSC]: Call osc_apdu_send.
* card-common.h (struct p15_private_s): Forward declaration. Add
it to card_ctx_s.
* card.c (card_close): Make sure private data is released.
(card_enum_certs): New.
* card-p15.c (p15_release_private_data): New.
(init_private_data): New to work around an OpenSC weirdness.
(p15_enum_keypairs): Do an OpenSC get_objects only once.
(p15_enum_certs): New.
(card_p15_bind): Bind new function.
* command.c (cmd_learn): Return information about the certificates.
it to card_ctx_s.
* card.c (card_close): Make sure private data is released.
* card-p15.c (p15_release_private_data): New.
(init_private_data): New to work around an OpenSC weirdness.
(p15_enum_keypairs): Do an OpenSC get_objects only once.
* call-agent.c (start_agent): Create and pass the list of FD to
keep in the child to assuan.
* call-dirmngr.c (start_dirmngr): Ditto.
* scdaemon.c (main): Use GNUPG_DEFAULT_HOMEDIR constant.
* assuan-pipe-connect.c (assuan_pipe_connect): No special handling
for the log_fd and stderr. Connect stderr to /dev/null if it
should not be retained.
* card.c (card_open): set it here.
* card-p15.c (p15_prepare_key): Factored out common code from ...
(p15_sign, p15_decipher): here and made the decryption work the
regular way.
