following the convention in other files eg., data_map.h -> DataMap& operator=(const DataMap&) = default;
just modifying to:
NodeId& operator=(const NodeId&) = default;

Now the builds are fine for arm-gcc as well.
Merge pull request #91 from ustulation/MAID-588_Debug-builds-with-arm-cross-compiler-fails

MAID-588 bug fix node_id.h unused variable warning