1. `brew install SergioBenitez/osxct/x86_64-unknown-linux-gnu`   
2. `brew install x86_64-linux-gnu-binutils` 
3. `rustup target add x86_64-unknown-linux-gnu`  
4. Edit `~/.cargo/config` and add
```
[target.x86_64-unknown-linux-gnu]
linker = "x86_64-unknown-linux-gnu-gcc"
```
5. `source ~/.cargo/config`
6. Edit `Cargo.toml` and include OpenSSL crate dependency **This is the part missing from many how-to**
```
[dependencies]
openssl = { version = "0.10", features = ["vendored"] }
```

cargo build --target x86_64-unknown-linux-gnu --release