Formatting and typos
Move setup_path into its own file.
Move setup_devpts into its own file.
Move setup_run into its own file.
Use the clone() system call instead of the glibc wrapper

The clone() glibc wrapper requires allocating your own child stack.
Since we don't use CLONE_VM, this is unnecessary.

We write our own my_clone() wrapper, which also takes over the
capability handling. This means that after clone(), the parent
loses all capabilities forever, while the child loses them
temporarily.