message: fixed build for < 4.21
diff: @@ -985,7 +985,11 @@ PyObject *py_ue_skeletal_mesh_build_lod(ue_PyUObject *self, PyObject * args, PyO
  points_to_map.Add(vertex_index);
  +#if ENGINE_MINOR_VERSION > 20
  SkeletalMeshImportData::FMeshWedge wedge;
  +#else
  + FMeshWedge wedge;
  +#endif
  wedge.iVertex = vertex_index;
  wedge.Color = ss_vertex->ss_vertex.Color;
  for (int32 i = 0; i < MAX_TEXCOORDS; i++)
  @@ -996,7 +1000,11 @@ PyObject *py_ue_skeletal_mesh_build_lod(ue_PyUObject *self, PyObject * args, PyO
  for (int32 i = 0; i < MAX_TOTAL_INFLUENCES; i++)
  {
  +#if ENGINE_MINOR_VERSION > 20
  SkeletalMeshImportData::FVertInfluence influence;
  +#else
  + FVertInfluence influence;
  +#endif
  influence.VertIndex = wedge_index;
  influence.BoneIndex = ss_vertex->ss_vertex.InfluenceBones[i];
  influence.Weight = ss_vertex->ss_vertex.InfluenceWeights[i] / 255.f;
  @@ -1018,7 +1026,11 @@ PyObject *py_ue_skeletal_mesh_build_lod(ue_PyUObject *self, PyObject * args, PyO
  for (int32 i = 0; i < wedges.Num(); i += 3)
  {
  +#if ENGINE_MINOR_VERSION > 20
  SkeletalMeshImportData::FMeshFace face;
  +#else
  + FMeshFace face;
  +#endif
  face.iWedge[0] = i;
  face.iWedge[1] = i + 1;
  face.iWedge[2] = i + 2;
  