Problem: Travis CI OSX builds are broken

Solution: add a workaround to reinstall libtool. Travis hasn't fixed
the issue in a month, so time for a little hack until they sort it.

Problem: getifaddrs can fail with ECONNREFUSED

getifaddrs() can fail transiently with ECONNREFUSED on Linux.
This has been observed with Linux 3.10 when multiple processes
call zmq::tcp_address_t::resolve_nic_name() simultaneously.

Before asserting in this case, make 10 attempts, with exponential
backoff, given by (1 msec * 2^i), where i is the attempt number.

Fixes #2051

Minor fixes/changes in Win32/MSVC build system

Solution: correct path is ../src/windows.hpp. Also added automatic linking
of iphlpapi library if required and using MSVC

only if the library is found at a specific path

Solution: Search for libzmq.lib in ../bin/Win32/Debug/v120/dynamic, don't
know how to automatically search in correct path based on current build
configuration

Problem: parameter %1 set hard to build target and prevents the skipp…

Solution: removed Pause

modified build.bat for msvc to support non-pausing script-based instal…

Signed-off-by: Bernd Langpap <Bernd.Langpap@airbus.com>

Problem: MSVC warns about event monitoring functions converting SOCKET to int

Add missing Git ignores.

Send manual unsubscriptions on pipe termination in XPUB

Expect custom messages on both explicit unsubscription and pipe termination.

Copy instead of reference to a vector that gets reallocated.

Flush stderr buffer before calling zmq_abort in assert macros

On Windows, the written message does not seem to be guaranteed to be
written to stderr, in particular when stderr is redirected to a file. I
suppose this is because RaiseException terminates the process in a way
that does not give the CRT a chance to flush stdio buffers (or if it
does, there might be a problem when more than one CRT instance is linked
into the program and they overwrite each other's exception handler). Either
way, just make sure the assertion message ends up written to stderr to
ease diagnostics.

Problem: FD_SETSIZE not set to 16k for all build definitions

Solution: Set FD_SETSIZE to 16k for all other build definitions.

Poll() implementation for Windows Vista+

Solution: Provide poll() for Windows as well. This is a build option that
defaults to off as the resulting binary will only run on Windows Vista or
newer.

This is not tested with alternative Winsock service providers like VMCI,
but the documentation for WSAPoll does not mention limitations.

On my local machine, throughput improves by ~10 % (20 simultaneous
remote_thr workes to one local_thr, 10 byte messages), while latency
improves by ~30 % (measured with remote/local_lat).

Solution: Always use fd_t when accessing the pollset.

Problem: std:vector.data breaks compat with C++98

Solution: use buffer address instead

Fix build error in MSVC11

(and probably other MSVC versions)

Problem: Android CI NDK version and C++ ABI are outdated

Solution: switch to 4.9

Solution: update CI scripts to use newer r11c from r10e

Solution: use a variable for easier maintenance, in sync with zproject

allow to build sparc (v8,leon)

Only set sparcv9 optimization for sparc64 systems.
This allows to run for example application using zeromq
on sparc32 systems.
Signed-off-by: Waldemar Brodkorb <wbx@uclibc-ng.org>

Problem: update zmq_setsockopt doc with new flag name