Cargo build fails with jobserver error


#1

While building a crate with several dependencies I keep running into an error that I cannot figure out:
error: failed to acquire jobserver token: Resource temporarily unavailable (os error 11)

Full output is available here:
http://paste.debian.net/999863/

What does the error mean? What can I do to avoid the issue?

rustc: 1.21.0
cargo: 0.22.0