Function configure_environment 

pub fn configure_environment(env: &mut Env, run: Run) -> Work

Get the environment ready for performing the work.

This function takes the parsed command-line arguments and applies them to the environment. It also sets up signal dispositions and prepares built-ins and variables. The function returns the work to be performed, which is extracted from the run argument.

This function is pure in that all system calls are performed by the System trait object (env.system).