changes for xent_op_gpu.cc device-side compilation
changes for xent_op_gpu.cc device-side compilation

hughperkins/coriander,hughperkins/cuda-on-cl,hughperkins/coriander,hughperkins/cuda-on-cl,hughperkins/coriander,hughperkins/coriander,hughperkins/cuda-on-cl,hughperkins/cuda-on-cl