* g10/options.h (opt): Add flags.full_timestrings.
* g10/gpg.c (oFullTimestrings): New.
(opts): New option.
(main): Set new flag.
* g10/keyid.c (dateonlystr_from_pk): New.
(dateonlystr_from_sig): New.
(datestr_from_pk): Divert to isotimestamp if requested.
(datestr_from_sig): Ditto.
(expirestr_from_pk): Ditto.
(expirestr_from_sig): Ditto.
(revokestr_from_pk): Ditto.
* g10/import.c (impex_filter_getval): Use dateonlystr_from_sig and
dateonlystr_from_pk.