Solution: guard CMake statement properly

Solution: apply naming style

Solution: added tests

Solution: specify not to use stdint.h for VS<=2008, fixes #3025

Solution: fix indentation

Solution: use regular zmq_socket instead in thread functions

Solution: increase timeout

Solution: disable test cases

Solution: use unity mechanism for ignoring with message

Solution: increase timeout, remove timeout settings for unsupported poll poller

Solution: add diagnostic output

Solution: use TEST_ASSERT_FAILURE_ERRNO

Solution: migrate to unity

Solution: migrate to unity

Solution: insert some sleeps to remedy timing dependencies

Solution: migrate to unity

Solution: migrate to unity

Solution: fix types

Solution: migrate to Unity

Solution: Use fd_t

Solution: Use size_t instead of int

Solution: Use unsigned char instead of size_t

Solution: Use unsigned char instead of size_t

Solution: Use fd_t

Solution: Use fd_t

Solution: explicitly compare function pointer against NULL

Solution: check and return an error on invalid arguments. Fixes #3088

Solution: re-enable them

Solution: change comment, and add test case for zmq_poller_modify with events == 0

Solution: migrate to unity assertions

Solution: if a PING message contains a context, echo it back in the
PONG message. In order to do so, create the PONG message when PING
is received and store it in the engine.
After the PING the engine goes straight to encoding and sending, so
there can always be at most one pending PING.
Add tests for various contexts.

Solution: remove it, it doesn't add much value anyway

Solution: migrate to unity

Solution: refactor the test code to work around aliasing issues

Solution: change the ifdef to always print on any Unix, as they
all have ulimit

Solution: use a different max socket value on Solaris, where the
default limit is 256 instead of 1024

Solution: add a new ZMQ_MULTICAST_LOOP option for UDP sockets.

Solution: pass the flags to zmq_recv

Solution: Add IPv6 support

Solution: Factor the code into a different file with a well defined API and add
unit tests.