core: Support --locate-external-keys command of gpg
* src/gpgme.h.in (GPGME_KEYLIST_MODE_FORCE_EXTERN): New. (GPGME_KEYLIST_MODE_LOCATE_EXTERNAL): New. * src/gpgme.c (gpgme_set_keylist_mode): Check for invalid mode. * src/engine-gpg.c (gpg_keylist_build_options): Use "--locate-external-keys" instead of "--locate-keys" if flag is set. * src/gpgme-json.c (op_keylist): New flag "force-extern". * src/gpgme-tool.c (gt_get_keylist_mode, cmd_keylist_mode): Handle new mode.
- GnuPG-bug-id: T5951