SSL: support for per-certificate chains. The SSL_CTX_add0_chain_cert() function as introduced in OpenSSL 1.0.2 now used instead of SSL_CTX_add_extra_chain_cert(). SSL_CTX_add_extra_chain_cert() adds extra certs for all certificates in the context, while SSL_CTX_add0_chain_cert() only to a particular certificate. There is no difference unless multiple certificates are used, though it is important when using multiple certificates. Additionally, SSL_CTX_select_current_cert() is now called before using a chain to make sure correct chain will be returned.