Don't link sftp, sftp-server or scp with libcrypto

[Damien Miller]

On Tue, 12 Jul 2022, Darren Tucker wrote:

> Hi.
> 
> This applies on top of my previous patch cleaning up libcrypt and stops
> linking scp, sftp and sftp-server against libcrypto.  Why do this?
> Well for one reason these components sometimes get used independently
> of ssh/sshd (eg in OpenWRT where they can be used with Dropbear) and
> it'd be nice if I could have sftp on space constrained devices without
> the currently-required but not strictly necessary additional libraries.
> 
> The same thing can be done with zlib but that's the next patch.

IIRC we linked libcrypto because some linkers were not smart enough to
elide references to libcrypto coming from unused functions in libssh

It's possible that I'm wrong/outdated though