Tracking issue for libstd/libredox compatibility.

Created by: ticki

Description: This issue tracks the compatibility between Redox's libstd ("libredox") and the upstream libstd.

List:

• Full IO compatibility. Done.
• Moving extras to a seperate library. Done.
• Lacking sync primitives:
  • Mutex.
  • mpsc.
  • Barrier.
  • CondVar.
  • Atomic types.
• Remove unnecessary reexports.
• Collections:
  • HashMap.
    • SipHasher.
  • HashSet
  • BTreeMap.
  • BTreeSet.
  • Vec.
  • VecDeque.
  • LinkedList.
• Networking:
  • CheckSum.
  • IPv4.
  • Ipv6.
  • Incoming.
  • TcpListener.
  • TcpStream.
  • UdpSocket.
  • LookupHost
• File management:
  • File.
  • canonicalize.
  • create_dir.
  • metadata.
  • read_dir.
  • remove_dir.
  • remove_file.
  • OpenOptions.
  • copy.
  • rename.
  • set_permissions.
  • soft_link.
  • hard_link.
  • read_link.
  • create_dir_all.
  • remove_dir_all.
  • Permissions.
  • DirBuilder.
• Time:
  • Duration.
  • Instant.
  • SystemTime.
  • SytemTimeError.
• Threading:
  • spawn.
  • sleep.
  • yield_now.
  • .join().
  • park.
  • park_timeout.
  • panicking.
  • LocalKey.
  • Builder.
  • current.
• Environment:
  • var.
  • set_var.
  • current_dir.
  • current_exe.
  • temp_dir.
  • remove_var.
  • join_paths.
  • args.
  • args_os.