crates.io build script guide: optional dependencies mistake?

[hobofan]

In the "Linking to system libraries" example of the build script guide it says:

It has a optional dependency on libssh2 on all platforms to implement the ssh transport.

A few lines later there is a contradicting statement while still talking about the same example:

Here we also see the unconditional dependency on libssh2 via the libssh2-sys crate

Am I missing something or should the former also read "unconditional dependency"?

[steveklabnik]

I think you're correct.

[alexcrichton]

This is actually intentional, but I think the antecedents may not be clear enough. "It" in the optional part is referring to libgit2 itself whereas later the "it" is the Rust crate which chose to have an unconditional instead of optional dependency.

[alexcrichton]

(I can see where this is confusing though!)