Fix cmake build
Merge pull request #864 from ricnewton/master

Fix cmake build
Fixed issue #865 - validation on ZMQ_TCP_KEEPALIVE
Merge pull request #866 from hintjens/master

Fixed issue #865 - validation on ZMQ_TCP_KEEPALIVE
Whitespace cleanups
Whitespace fix
Fixed issue #868
Merge pull request #870 from hintjens/master

Fixed issue #868
Fix potential segmentation fault

Call the allocation assertion macro before dereferencing the socket
pointer.
Fix potential memory leak

Delete the socket if the initialization part of the socket creation
fails.
Merge pull request #871 from apyrgio/develop

Fix potential segfault/memleak
Added ZMQ_BUILD_TESTS to CMakeLists.txt to allow turning off tests. Useful when building ZMQ as a git submodule.
Merge pull request #874 from gyulalaszlo/cmake-switchable-tests

Added ZMQ_BUILD_TESTS to CMakeLists.txt to allow turning off tests.