* src/gpgme.h.in (gpgme_verify_flags_t): New enum.
(GPGME_VERIFY_ARCHIVE): New const.
(gpgme_op_verify_ext_start): New func.
(gpgme_op_verify_ext): New func.
* src/gpgme.def, src/libgpgme.vers: Add new functions.
* src/verify.c (gpgme_op_verify_ext_start): New.
(gpgme_op_verify_ext): New.
(verify_start): Add arg FLAGS.  Pass the flags to
_gpgme_engine_op_verify.
(gpgme_op_verify_start): Call gpgme_op_verify_ext_start with 0 for
FLAGS.
(gpgme_op_verify): Call gpgme_op_verify_ext with 0 for FLAGS.
* src/engine.c, src/engine.h (_gpgme_engine_op_verify): Add arg FLAGS.
* src/engine-backend.h (struct engine_ops): Add FLAGS to 'verify'.
* src/engine-gpg.c (gpg_verify): Add arg FLAGS. Set use_gpgtar engine
flag if GPGME_VERIFY_ARCHIVE flag is set. Check for new enough gpg. Use
add_gpg_arg for gpg-only options without a value. Set extra options for
gpgtar and pass input data to stdin when using gpgtar.
* src/engine-gpgsm.c (gpgsm_verify): Add arg FLAGS. Return error if
GPGME_VERIFY_ARCHIVE flag is set.
* src/engine-uiserver.c (uiserver_verify): Ditto.
* tests/run-verify.c (show_usage): New options --archive, --directory,
and --diagnostics.
(main): Parse new options. Verify and extract with gpgtar if --archive
is given. Set file name of output data to value of --directory option.
Print stderr of gpg/gpgtar if --diagnostics is given.