This is new warning introduced with GCC 8. This is being fixed by using appropriate function, like g_queue_free_full/g_list_free_full or by casting to GCallback before casting to the target function signature.
Closes: #46
The add_to_be_sent was duplicated in http/socks5/pseudossl/tcp-bsd and
had some small differences. It's better to factor it out so bug fixes
get applied to all of them and code is cleaner.