This doesn't embed ALL the options for the ssh client, but I based it
on options I use regularly. Here's an example usage extracted and
edited from my home.nix:
```nix
programs.ssh = {
enable = true;
forwardAgent = true;
controlMaster = "auto";
hosts = {
"something.blah.edu" = {
port = 1024;
user = "cleague";
identitiesOnly = true;
};
"host1 host2 host2.net host2.com" = {
port = 7422;
hostname = "example.com";
serverAliveInterval = 60;
};
"lucian" = {
forwardX11 = true;
forwardX11Trusted = true;
checkHostIP = false;
};
};
};
```
For example, with these settings Bash will complain if uninitialized
variables are used. Some code has been improved to run cleanly with
these settings.
If the dconf service hasn't been installed then the configuration
activation will fail. Thus, make sure the activation script is run after
packages have been installed.
