Solution: always initialised zmq::options_t class variables arrays to
avoid reading uninitialised data when CURVE is not yet configured and
a getsockopt ZMQ_CURVE_{SERVER | PUBLIC | SECRET]KEY is issued.

Various test fixes

Solution: increase SETTLE_TIME from 50ms to 300ms to avoid failing on
slower environments like through Valgrind on slow VMs.

Solution: suggest to use the common approach of msleep (SETTLE_TIME)
after a connect if necessary, rather than reimplementing a different
way.

Solution: include pthread.h in testutil.hpp, removed from
test_shutdown_stress_tipc in an earlier commit

Solution: rename from test_socketopt_hwm to test_sockopt_hwm in
.gitignore too

Solution: add msleep (SETTLE_TIME) to test_immediate, test_spec_rep
and test_spec_router after the sockets are created and connected to
avoid failing when running in slower environment like through
Valgrind in underpowered VMs.

Solution: use msleep (SETTLE_TIME) everywhere when waiting for the
connections/sockets to be settled instead of a variety of patterns
and functions to make tests more coherent.

Solution: memset temporary buffer before use to reduce Valgrind noise

Solution: memset temporary buffer before use to reduce Valgrind noise

Solution: close socket and destroy context to reduce Valgrind noise

Solution: memset temporary buffer before use to reduce Valgrind noise

Solution: free addrinfo to reduce Valgrind noise

Solution: close socket and destroy context to reduce Valgrind noise

Solution: pass correct size to memcmp to avoid reading uninitialised
areas of the buffer.

Solution: close socket and destroy context to reduce Valgrind noise

Problem: too many CI builds

Solution: remove libsodium and no curve builds from cmake and android

Problem: tests don't build on Windows

There were numerous small issues with test cases:

- some lacked the right source file header
- some were not portable at all
- some were using internal libzmq APIs (headers)

Solution: fixed and cleaned up.

Cleaning up Windows build for gyp

There were numerous small issues with test cases:

- some lacked the right source file header
- some were not portable at all
- some were using internal libzmq APIs (headers)

Solution: fixed and cleaned up.

Solution: document the minimum rules in README.md

Solution: offer a build.bat to help the user.

Making gyp builds work

Solution: it's a lot of work to define the tests in project.gyp
so I did this using gsl to generate the JSON, from a small XML
list of the test cases.

To keep this, and the hundreds of .mk files, away from the root
directory, I've moved the gyp files into builds/gyp, where you
would run them.

It all seems to work now. Next up, OS/X and Windows :)

Doesn't affect building, just potentially confusing.

Solution: fix it.

It's all over the place.

Solution: remove duplicates and try to move main includes to start
of source. Also, include net/if.h always, so that the code will
compile if ZMQ_HAVE_IFADDRS isn't defined.

This is rather insane since the code knows well enough what systems
support if_nametoindex. I blame this on over-use of autotools early
in libzmq's days.

Anyhow, this breaks gyp builds on OS/X.

Solution: add ZMQ_HAVE_IFADDRS to build/gyp/platform.hpp for OS/X.

Getting gyp build working

Solution: add necessary macros into builds/gyp/platform.hpp

Work for Linux now, other platforms to test.

Problem: CI use of sodium or nacl is confusing

Solution: establish a matrix of CI options. On one axis we have the
build system (autotools, cmake, android) and on the other axis we
have the encryption options (tweetnacl, libsodium or none).

Problem: typo in CMake platform.hpp breaks build

Solution: use ZMQ_USE_TWEETNACL as a define as expected instead of
HAVE_TWEETNACL

I'm adding gyp support so that we can easily pull in libzmq
and other C/C++ projects into gyp packages, especially via
node-gyp.

Solution: add gyp definition

This works only for Windows, OS/X, and Linux. We set a single
macro in project.gyp according to the system, and the rest is
done in builds/gyp/platform.hpp. The values in that file are
not dynamic. Your mileage will vary.

Problem: CI is borken

Solution: if not building with tweetnacl, do not include its sources
in Makefile.am. CMake already includes them optionally.

Solution: must be upper case

Solution: check for WITH_LIBSODIUM configure option instead of
WITH_SODIUM