* g10/gpg.c (parse_list_options): Add new option.
* g10/options.h (LIST_SHOW_X509_NOTATIONS): New.
* g10/build-packet.c (search_sig_notations): New.
* g10/keylist.c (print_x509_notations): New.
(list_signature_print): Use macros for the sig classes.  Call
print_x509_notations.
(list_keyblock_print): Call list_signature_print if x509 notation
printing is enabled.