109.52.00

- Added `Unix.File_descr.equal`.
- Added `Lock_file.Nfs.unlock`, the `Or_error` version of
  `unlock_exn`.
- Improved the detail of the error messages exposed by
  `Lock_file.Nfs.create{,_exn}`.
- Added `Unix.set_mcast_ifname`, to control the interface used for UDP
  multicast traffic.

  Added bindings for setsockopt `IP_MULTICAST_IF`.

  See 6.3 in: http://www.tldp.org/HOWTO/Multicast-HOWTO-6.html
- Changed `Command` argument processing to treat a single dash (`-`)
  as an anonymous argument rather than a flag.

  This change follows the unix convention of passing `-` as an
  anonymous argument meaning `stdin`.
- Added more bin-prot support to `Iobuf`: `Consume.bin_prot`,
  `Fill.bin_prot`, `Peek.bin_prot`, `Poke.bin_prot`.

  Framing doesn't do much for `Iobuf`, so these are to be more
  standard, unframed accessors, as opposed to `fill_bin_prot`.
- Added `Core.Debug.am`, `amf`, and `ams`, for outputting debugging
  messages showing the current source-code position.

  Unfortunately, these aren't available in `Core.Std.Debug`, but only
  in `Core.Debug`.  That will be fixed in 109.49.
- Made `Time_stamp_counter` compile on non x86-64 platforms.
- Made `Core.Std.Debug` be `Core.Debug` rather than
  `Core_kernel.Debug`.

  This exposes the `Debug.am*` functions added in 109.48.