Socks5 and TLS handshake failures in Debian Jessie and Ubuntu Xenial

[jgaa]

I have observed a weird error where initial binary handshakes (TLS and Socks5) fails with error 11 (EAGAIN) on these systems, at least when running in Docker and communicating with a server outside the container. It could be related to old versions of the boost library. If I link with boost 1.76, the socks5 tests pass.