zsys_udp_send: Report send errors to stderr.
zbeacon: Makes broadcast work with OSX
Merge pull request #537 from hintjens/master

gossip fixes
Merge pull request #538 from ahhentz/master

Trying to fix zbeacon in OSX
Fix CMake include search on MacOS X
Merge pull request #539 from guidefloripa/master

Fix CMake include search on MacOS X
Fix header inclusion order fix
This fixes a header inclusion order bug in czmq_prelude.h

If you're compiling on linux with gcc -std=c99 _AND_
you are including czmq.h _after_ stdint.h _and_
you are not defining _BSD_SOURCE _before_ stdint.h,
uint is not properly defined, causing a build error.
This patch fixes that error. It also fixes the feature detect
code for Linux hosts.
Merge pull request #540 from jricher42/master

Fix header inclusion order fix
Problem: does not initialize system before running selftest

This fails on Windows. Solution: call zsys_init() at start of
selftest method.

Fixes #542.