Repost: [patch] Automatically add keys to agent

[joshua stein]

> I am a bit disappointed by the total lack of response - does nobody else
> have this problem?

i like it.

i have xlock running "ssh-add -D" before locking the screen and
"ssh-add" again after unlocking, but that requires entering the key
passphrase after every unlock, even if i don't use ssh before
locking again.  with your patch i can just wait until i have to use
ssh first before adding the key back to the agent.  this is how ssh
works on mac os x with its integrated keychain support.

my only comment about the code itself might be to change oAddKey and
add_key to something with "agent" in the name, just for clarity when
reading through it later.