Require at least cmake 3.11 to run examples, as its required in main CMakeLists.txt file. Newer cmake issue errors with version less then 3.5 See e.g. https://bugs.debian.org/1040723
without this, compilation failed with /usr/bin/ld: cannot find -lcppzmq
Solution: Compile the examples when tests are compiled and using C++11 or greater.