Log Message:
zeromq: updated to 4.2.5

0MQ version 4.2.5 stable:
* Fixed 3018 - fix backward-incompatible change in the NULL auth
                mechanism that slipped in 4.2.3 and made connections
                with a ZAP domain set on a socket but without a working
                ZAP handler fail. See ZMQ_ZAP_ENFORCE_DOMAIN and RFC27.
* Fixed 3016 - clarify in zmq_close manpage that the operation will
                complete asynchronously.
* Fixed 3012 - fix CMake build problem when using LIBZMQ_WERROR and a
                compiler other than GCC.

0MQ version 4.2.4 stable:
* New DRAFT (see NEWS for 4.2.0) socket options:
  - ZMQ_LOOPBACK_FASTPATH to enable faster TCP loopback on Windows
  - ZMQ_METADATA to set application-specific metadata on a socket
  See doc/zmq_setsockopt.txt and doc/zmq_getsockopt.txt for details.
* New DRAFT (see NEWS for 4.2.0) context options:
  - ZMQ_ZERO_COPY_RECV to disable zero-copy receive to save memory
    at the expense of slower performance
  See doc/zmq_ctx_set.txt and doc/zmq_ctx_get.txt for details.
* New DRAFT API zmq_stopwatch_intermediate which returns the time
  elapsed without stopping the stopwatch.
* TIPC: support addressing TIPC Port Identity addresses.
* Added CMake option to disable tests: BUILD_TESTS
* Added CMake and autotools make targets to support clang-formatter:
  make clang-format, clang-format-check and clang-format-diff to
  help developers make sure their code conforms to the style guidelines
* For distributors: a new test framework has been added, which
  includes a copy of the Unity source code. This source code library is
  distributed under the MIT license and thus is compatible with
  libzmq's LGPL3.
* Fixed 2867 - add ZeroMQConfig.cmake.in to distributable tarball
* Fixed 2868 - fix OpenBSD build
* Fixed 2870 - fix VC++ 11.0 (VS2012) build
* Fixed 2879 - prevent duplicate connections on PUB sockets
* Fixed 2872 - fix CMake tests on Windows
* Fixed 2895 - fix assert on Windows with POLL
* Fixed 2920 - fix Windows build with Intel compiler
* Fixed 2930 - use std::atomic when available with VC++ and VS2015
* Fixed 2910 - fix race condition with ZMQ_LINGER socket option
* Fixed 2927 - add support for ZMQ_XPUB_NODROP on ZMQ_RADIO
* Fixed 2820 - further clarify ZMQ_XPUB_VERBOSE(R) documentation.
* Fixed 2911 - ZMQ_DISH over UDP triggers errno_assert() after hitting
                watermark
* Fixed 2942 - ZMQ_PUB crash when due to high volume of subscribe and
                unsubscribe messages, an unmatched unsubscribe message is
                received in certain conditions
* Fixed 2946 - fix Windows CMake build when BUILD_SHARED is off
* Fixed 2960 - fix build with GCC 8
* Fixed 2967 - fix race condition on thread safe sockets due to pthread
                condvar timeouts on OSX
* Fixed 2977 - fix TIPC build-time availability check to be more relaxed
* Fixed 2966 - add support for WindRiver VxWorks 6.x
* Fixed 2963 - fix some PVS Studio static analysis warnings
* Fixed 2983 - fix MinGW cross-compilation
* Fixed 2991 - fix mutex assert at shutdown when the zmq context is part
                of a class declared as a global static