SSL_CTRL_CHAIN
SSL_CTX_ctrl(ctx, SSL_CTRL_CHAIN, 0, (char *)(sk))
SSL_CTX_ctrl(ctx, SSL_CTRL_CHAIN, 1, (char *)(sk))
SSL_ctrl(s, SSL_CTRL_CHAIN, 0, (char *)(sk))
SSL_ctrl(s, SSL_CTRL_CHAIN, 1, (char *)(sk))
case SSL_CTRL_CHAIN:
case SSL_CTRL_CHAIN: