gpg: Add signature cache support to the keybox.
* g10/keydb.c (parse_keyblock_image): Add arg SIGSTATUS. (keydb_get_keyblock): Handle it. (build_keyblock_image): Add arg SIGSTATUS. (keydb_insert_keyblock): Handle it. * kbx/keybox-blob.c (pgp_create_sig_part): Add arg SIGSTATUS. (_keybox_create_openpgp_blob): Ditto. * kbx/kbxutil.c (import_openpgp): Adjust for above change. * kbx/keybox.h (KEYBOX_FLAG_SIG_INFO): New. * kbx/keybox-search.c (_keybox_get_flag_location): Handle new flag. (keybox_get_keyblock): Add arg R_SIGSTATUS. * kbx/keybox-update.c (keybox_insert_keyblock): Add arg SIGSTATUS.
With this change a key listing using the keybox format is now double
as fast as using a keyring. The memory use dropped as well. Measured
with about 1500 keys.