Log Message:
zeromq: updated to 4.2.3

version 4.2.3 stable:

* API change: previously ZMQ_POLLOUT on a ZMQ_ROUTER socket returned always
  true due to how the type works. When ZMQ_ROUTER_MANDATORY is set, sending
  fails when the peer is not available, but ZMQ_POLLOUT always returns true
  anyway, which does not make sense. Now when ZMQ_ROUTER_MANDATORY is set,
  ZMQ_POLLOUT on a ZMQ_ROUTER will return true only if at least one peer is
  available.
  Given ZMQ_POLLOUT with ZMQ_ROUTER was not usable at all previously, we do
  not consider this a breakage warranting a major or minor version increase.

* ZMQ_IDENTITY has been renamed to ZMQ_ROUTING_ID and ZMQ_CONNECT_RID has been
  renamed to ZMQ_CONNTECT_ROUTING_ID to disambiguate. ZMQ_IDENTITY and
  ZMQ_CONNECT_RID are still available to keep backward compatibility, and will
  be removed in a future release after further advance notice.

* DRAFT API change: zmq_poller_wait, zmq_poller_wait_all and zmq_poller_poll
  have been changed to be inline with other existing APIs that have a timeout
  to return EAGAIN instead of ETIMEDOUT as the errno value.

* Existing non-DRAFT socket types ZMQ_REP/REQ, ZMQ_ROUTER/DEALER and
  ZMQPUB/SUB, that were previously declared deprecated, have been reinstated
  as stable and supported.

* Tweetnacl: add support for, and use preferably if available, getrandom() as
  a simpler and less error-prone alternative to /dev/urandom on OSes where it
  is available (eg: Linux 3.18 with glibc 2.25).

* Curve: all remaining traces of debug output to console are now removed, and
  new DRAFT events are available to properly debug CURVE, PLAIN, GSSAPI and
  ZAP events and failures. See below for details on the new events.

* New DRAFT (see NEWS for 4.2.0) socket options:
  - ZMQ_GSSAPI_PRINCIPAL_NAMETYPE and ZMQ_GSSAPI_SERVICE_PRINCIPAL_NAMETYPE, for
    the corresponding GSSAPI features. Additional definitions for principal
    name types:
    - ZMQ_GSSAPI_NT_HOSTBASED
    - ZMQ_GSSAPI_NT_USER_NAME
    - ZMQ_GSSAPI_NT_KRB5_PRINCIPAL
    See doc/zmq_gssapi.txt for details.
  - ZMQ_BINDTODEVICE (Linux only), which will bind the socket(s) to the
    specified interface. Allows to use Linux VRF, see:
    https://www.kernel.org/doc/Documentation/networking/vrf.txt
    NOTE: requires the program to be ran as root OR with CAP_NET_RAW
  - ZMQ_ZAP_ENFORCE_DOMAIN, enables strict RFC 27 compatibility mode and makes
    the ZAP Domain mandatory when using security. See:
    https://rfc.zeromq.org/spec:27/ZAP
  See doc/zmq_setsockopt.txt and doc/zmq_getsockopt.txt for details.

* New DRAFT (see NEWS for 4.2.0) context options:
  - ZMQ_THREAD_AFFINITY_CPU_ADD and ZMQ_THREAD_AFFINITY_CPU_REMOVE (Posix only),
    to add and remove CPUs to the affinity set of the I/O threads. Useful to pin
    the background threads to specific CPUs.
  - ZMQ_THREAD_NAME_PREFIX (Posix only), to add a specific integer prefix to the
    background threads names, to easily identify them for debugging purposes.
  See doc/zmq_ctx_set.txt and doc/zmq_ctx_get.txt for details.

* New DRAFT (see NEWS for 4.2.0) message property name definitions to facilitate
  the use of zmq_msg_gets:
  - ZMQ_MSG_PROPERTY_ROUTING_ID
  - ZMQ_MSG_PROPERTY_SOCKET_TYPE
  - ZMQ_MSG_PROPERTY_USER_ID
  - ZMQ_MSG_PROPERTY_PEER_ADDRESS
  See doc/zmq_msg_gets.txt for details.

* New DRAFT (see NEWS for 4.2.0) API zmq_socket_get_peer_state, to be used to
  query the state of a specific peer (via routing-id) of a ZMQ_ROUTER socket.

* New DRAFT (see NEWS for 4.2.0) Socket Monitor events:
  - ZMQ_EVENT_HANDSHAKE_FAILED_NO_DETAIL, unknown system error and returns errno
  - ZMQ_EVENT_HANDSHAKE_SUCCEEDED, handshake was successful
  - ZMQ_EVENT_HANDSHAKE_FAILED_PROTOCOL, protocol errors between peers or server
    and ZAP handler. Returns one of ZMQ_PROTOCOL_ERROR_* - see manpage for list
  - ZMQ_EVENT_HANDSHAKE_FAILED_AUTH, failed authentication, returns ZAP status
  These events trigger when the ZMTP security mechanism handshake is
  completed or failed. See doc/zmq_socket_monitor.txt for more information.

* New DRAFT (see NEWS for 4.2.0) zmq_proxy_steerable command 'STATISTICS' to
  retrieve stats about the amount of messages and bytes sent and received by
  the proxy. See doc/zmq_proxy_steerable.txt for more information.

* Add new autoconf --disable-libunwind option to stop building with libunwind
  even if it is available.

* Add new autoconf --disable-Werror option to avoid building with the Werror
  flag.

* Use pkg-config as the first method for finding and building with external
  optional dependencies such as libnorm, libpgm and gssapi.

* On Posix platform where the feature is available, name the ZMQ background
  threads to simplify debugging: "ZMQbg/<num_thread>"

* Improve performance of zmq_poller_* (and zmq_poll and zmq_proxy when building
  with DRAFT APIs enabled).

* The TCP unit tests have been refactored to bind and connect to random ports
  rather than hard-coded ones, to allow running tests in parallel.
  There are 6 exceptions where it is necessary to use an hard-coded port to
  test specific code paths that would not be exercised when binding to a
  wildcard port. These are listed in tests/testutil.hpp so that distributions
  can easily patch them if they wish to and so that they can be unique across
  all the tests, allowing parallel runs.
  The IPC unit tests have been changed as well to use unique socket file names
  per test, where before there were some clashes.

* Fixed 2349 - fix building with libsodium when using CMake

* Fixed 2334 - do not assert when tuning socket options fails due to network
  errors, but simply retry again when connecting or send a socket monitor
  ZMQ_EVENT_ACCEPT_FAILED event when binding

* Fixed 2341 - fix source files path in VS2015 solution

* Fixed 2344 - Note that on Windows with VS2012 it is mandatory to increase
  the default stack size to at least 2MB

* Fixed 2348 - ZMQ_ROUTER send with ZMQ_ROUTER_MANDATORY can be stuck in case of
  network problem

* Fixed 2358 - occasional abort on zmq_connect on Windows

* Fixed 2370 - zmq_curve_keypair should return an error on failure rather
  than ignoring them and always returning 0

* Fixed 2452 - __STDC_LIMIT_MACROS before precompiled headers causes VC++
  warning

* Fixed 2457 - fix building with libsodium in Visual Studio solutions

* Fixed 2466 - add const qualifier to internal and public API that does not
  modify parameters

* Fixed 2471 - do more checks for OOM conditions when dynamic allocations is
  used

* Fixed 2476 - assertion causes abort after ZAP stop at shutdown

* Fixed 2479 - improve zmq_poller performance on Windows

* Fixed 2481 - potential memory leaks due to ZMTP handshake failures

* Fixed 2531 - ZMQ_GSSAPI_PRINCIPAL sockopt has no effect on client side

* Fixed 2535 - add BUILD_SHARED and BUILD_STATIC options to CMake, both on by
  default, to toggle shared and static library builds

* Fixed 2537 - use SYSTEM_CLOCK on OSX and CLOCK_MONOTONIC elsewhere for
  internal timers to avoid races

* Fixed 2540 - new zmq_poller used by zmq_poll without DRAFTs

* Fixed 2552 - Fix WITH_DOC CMake build to avoid checking for asciidoc if the
  option is disabled

* Fixed 2567 - Memory leak in REP socket handling

* Fixed 2579 - Compilation issue on Windows with CMake + ninja

* Fixed 2588 - SIGBUS under 64-bit SunOS Sparc

* Fixed 2590 - crash when using ZMQ_IMMEDIATE and ZMQ_LINGER to non-zero

* Fixed 2601 - XPUB_MANUAL subscriptions not removed on peer term

* Fixed 2602 - intermittent memory leak for ZMQ_REQ/REP send/recv

* Fixed 2608 - CURVE server (connect) fails when client rebinds

* Fixed 2610 - print backtraces in mutual exclusion to avoid mixing
  different traces

* Fixed 2621 - add missing CMake files to distributable tarball

* Fixed 2630 - improve compatibility with OpenBSD w.r.t. IPV6_V6ONLY

* Fixed 2638 - note in INSTALL that when using Windows builds on Linux with
  Wine it is necessary to increase the minimum TCP buffers

* Fixed 2632 - Fix file descriptor leak when using Tweetnacl (internal NACL
  implementation) instead of Libsodium, and fix race condition when using
  multiple ZMQ contexts with Tweetnacl

* Fixed 2681 - Possible buffer overflow in CURVE mechanism handshake.
  NOTE: this was protected by an assert previously, so there is no security
  risk.

* Fixed 2704 - test_sockopt_hwm fails occasionally on Windows

* Fixed 2701 - pgm build via cmake doesn't link libzmq with libpgm

* Fixed 2711 - ZAP handler communication errors should be handled consistently

* Fixed 2723 - assertion in src\select.cpp:111 or hang on zmq_ctx_destroy on
  Windows

* Fixed 2728 - fix support O_CLOEXEC when building with CMake

* Fixed 2761 - improve compatibility with TrueOS (FreeBSD 12)

* Fixed 2764 - do not unlink IPC socket files when closing a socket to avoid
  race conditions

* Fixed 2770 - support lcov 1.13 and newer

* Fixed 2787 - add libiphlpapi to PKGCFG_LIBS_PRIVATE for static mingw builds

* Fixed 2788 - document that adding -DZMQ_STATIC is required for Windows
  static builds with Mingw

* Fixed 2789 - description of zmq_atomic_counter_value return value is cloned
  from zmq_atomic_counter_new

* Fixed 2791 - fix building with DRAFT APIs on CentOS 6

* Fixed 2794 - router_t methods should not allocate memory for lookup in
  outpipes

* Fixed 2809 - optimize select() usage on Windows

* Fixed 2816 - add CMake and autoconf check for accept4, as it is not
  available on old Linux releases, and fallback to accept + FD_CLOEXEC

* Fixed 2824 - ZMQ_REQ socket does not report ZMQ_POLLOUT when ZMQ_REQ_RELAXED
  is set

* Fixed 2827 - add support for Haiku

* Fixed 2840 - fix building with VS2008

* Fixed 2845 - correct the ZMQ_LINGER documentation to accurately reflect that
  the default value is -1 (infinite). It never was 30 second in any released
  version, it was only changed briefly and then changed back, but the manpage
  was not reverted.

* Fixed 2861 - CMake/MSVC: export ZMQ_STATIC when needed.