testelctrodynamic fails with clang

The problem is line https://gitlab.dune-project.org/pdelab/dune-pdelab/blob/master/dune/pdelab/localoperator/electrodynamic.hh#L280

Error: variable length array of non-POD element type 'Curl' (aka 'FieldVector<double, dimOfCurl(dimR)>')

It is not standard conforming, g++ is fine with it, but clang (3.8 here) refuses it. Same compiler situation reported here: http://stackoverflow.com/questions/20461424/error-variable-length-array-of-non-pod-element-type-string