[Fix] Remove warnings in compilation (#1675)

* [Fix] remove warnings in compilation

* [Fix] fix order of statements

* [Fix] fix build error on windows

* cannel buildextension wrapper

mmcv/ops/csrc/parrots/contour_expand.cpp

@@ -102,7 +102,6 @@ std::vector<std::vector<int>> contour_expand(Tensor kernel_mask,
   IntArrayRef data_shape = kernel_mask.sizes();
 
   auto data_label_map = internal_kernel_label.data_ptr<int32_t>();
-  IntArrayRef label_map_shape = internal_kernel_label.sizes();
   vector<vector<int>> text_line;
 
   kernel_dilate(ptr_data, data_shape, data_label_map, kernel_num,

mmcv/ops/csrc/pytorch/cpu/pixel_group.cpp

@@ -105,7 +105,7 @@ std::vector<std::vector<float>> pixel_group_cpu(
 
       float dis = 0;
       auto ptr_embedding_tmp = ptr_embedding + tmpy * width * embedding_dim;
-      for (size_t i = 0; i < embedding_dim; i++) {
+      for (size_t i = 0; i < size_t(embedding_dim); i++) {
         dis +=
             pow(kernel_cv[i] - ptr_embedding_tmp[tmpx * embedding_dim + i], 2);
         // ignore further computing if dis is big enough