memory allocator, e.g. `-DMG_MALLOC=my_malloc`-`MG_USE_READ_WRITE` when set replaces calls to `recv` with `read` and `send` with `write`, thus enabling to add any kind of file descriptor (files, serial devices) to an event manager.-`MG_SSL_CRYPTO_MODERN`, `MG_SSL_CRYPTO_OLD` - choose either "Modern" or "Old" ciphers instead of the default "Intermediate" setting. See [this article](https://wiki.mozilla.org/Security/Server_Side_TLS#Recommended_configurations) for details.