C++14 is default in clang/gcc anyway and latest log4cxx requires C++17.
Qt on Ubuntu 18.04 sets C++11. Hence we use MoveIt's cmake macro to ensure C++14 at least.
... in favor of checking version numbers.
Checking for one header was used for multiple independent things.
In theory we could do exact feature testing instead of using the next release number,
but in practice nobody cares about the individual commits between older releases.