message: fixes a compilation error on cray with icc
  the error reads like
  "error: cannot convert 'float ' to 'const float ()[8]' for argument '4'
  environment was:
  icc 18.0.5, ispc 1.9.2, embree 3.2.0, ospray 1.8.4 all within craype 2.5.6
diff: @@ -164,12 +164,15 @@ export uniform float LocalFrameBuffer_accumulateTile(void *uniform _fb,
  export void LocalFrameBuffer_accumulateAuxTile(void *uniform _fb
  , const uniform Tile &tile
  , uniform vec3f *uniform aux
  - , const varying float * uniform ax
  - , const varying float * uniform ay
  - , const varying float * uniform az
  + , const void * uniform _ax
  + , const void * uniform _ay
  + , const void * uniform _az
  )
  {
  uniform LocalFB *uniform fb = (uniform LocalFB *uniform)_fb;
  + const varying float * uniform ax = (const varying float * uniform) _ax;
  + const varying float * uniform ay = (const varying float * uniform) _ay;
  + const varying float * uniform az = (const varying float * uniform) _az;
  const uniform float accumID = tile.accumID;
  const uniform float accScale = rcpf(tile.accumID + 1);
  