message: Fix amalgamated build
  Triangle adjacency is used in clusterizer and vertex cache optimizer;
  for now just rename the symbols to avoid conflicts.
diff: namespace meshopt
  {
  -struct TriangleAdjacency
  +struct TriangleAdjacency2
  {
  unsigned int* counts;
  unsigned int* offsets;
  unsigned int* data;
  };
  -static void buildTriangleAdjacency(TriangleAdjacency& adjacency, const unsigned int* indices, size_t index_count, size_t vertex_count, meshopt_Allocator& allocator)
  +static void buildTriangleAdjacency(TriangleAdjacency2& adjacency, const unsigned int* indices, size_t index_count, size_t vertex_count, meshopt_Allocator& allocator)
  {
  size_t face_count = index_count / 3;
  @@ -469,7 +469,7 @@ size_t meshopt_buildMeshlets(meshopt_Meshlet* destination, const unsigned int* i
  assert(max_vertices <= 255);
  assert(max_triangles <= sizeof(meshlet.indices) / 3);
  - TriangleAdjacency adjacency = {};
  + TriangleAdjacency2 adjacency = {};
  buildTriangleAdjacency(adjacency, indices, index_count, vertex_count, allocator);
  unsigned int* live_triangles = allocator.allocate<unsigned int>(vertex_count);
  