* g10/gpg.c (oChUid): New.
(opts): Add --chuid.
(main): Implement --chuid. Delay setting of homedir until the new
chuid is done.
* sm/gpgsm.c (main): Delay setting of homedir until the new chuid is
done.
* tools/gpg-card.c (oChUid): New.
(opts): Add --chuid.
(changeuser): New helper var.
(main): Implement --chuid.
* tools/gpg-connect-agent.c (oChUid): New.
(opts): Add --chuid.
(main): Implement --chuid.
--
Signed-off-by: Werner Koch <wk@gnupg.org>