This crate provides a #[dynpath()] macro that can be placed a mod statement and which points
the module to a dynamic path.
The macro takes a single parameter which is the name of an environment variable to read the path
from, and it appends the module name and .rs extension onto the contents of the variable.
Example
// Turns into `#[path = "whatever/is/in/OUT_DIR/bindings.rs"]`.