title: Specify Non-Standard Source Folder
body: <p>I am writing a multi-language project (a Java library which loads and calls Rust functions through the FFI), and so I want to divide my code files up a little bit. Rather than just putting everything in <code>src</code>, I've made folders <code>src/rust</code> and <code>src/java</code>. How can I tell Cargo that my <code>lib.rs</code> file (and all of my other source files) is in <code>src/rust</code> rather than <code>src</code>? Additionally, how can I tell it to output to <code>out/rust</code> rather than <code>target</code>?</p>