message: Implement hcc_{index_}bvh with hcc::device_vector
diff: #ifdef __HCC__
  #include "hcc/compat.h"
  +#include "hcc/device_vector.h"
  #endif
  namespace visionaray
  @@ -451,6 +452,13 @@ template <typename P>
  using cuda_index_bvh = index_bvh_t<thrust::device_vector<P>, thrust::device_vector<bvh_node>, thrust::device_vector<unsigned>>;
  #endif
  +#ifdef __HCC__
  +template <typename P>
  +using hcc_bvh = bvh_t<hcc::device_vector<P>, hcc::device_vector<bvh_node>>;
  +template <typename P>
  +using hcc_index_bvh = index_bvh_t<hcc::device_vector<P>, hcc::device_vector<bvh_node>, hcc::device_vector<unsigned>>;
  +#endif
  +
  //-------------------------------------------------------------------------------------------------
  // build() interface
  