Revert "Remove THC from OSS build (#134969)"

This reverts commit 9c7660be0ee155baf0cb7e1e67708dd784ac5796.

Reverted https://github.com/pytorch/pytorch/pull/134969 on behalf of https://github.com/huydhn due to Sorry for reverting your change but it is breaking the installation of https://github.com/facebookresearch/detectron2/blob/main/detectron2/layers/csrc/deformable/deform_conv_cuda_kernel.cu#L76 ([comment](https://github.com/pytorch/pytorch/pull/134969#issuecomment-2499275378))

BUILD.bazel

@@ -301,6 +301,7 @@ cc_library(
             "aten/src/**/*.hpp",
             "aten/src/ATen/cuda/**/*.cuh",
             "aten/src/ATen/native/**/*.cuh",
+            "aten/src/THC/*.cuh",
         ],
     ) + [
         ":aten_src_ATen_config",

aten/CMakeLists.txt

@@ -79,9 +79,11 @@ if(USE_ROCM)
   # TODO: AT_HIP_ENABLED (change this once we represent HIP as HIP in
   # ATen proper)
   set(AT_CUDA_ENABLED 1)
+  add_subdirectory(src/THH)
   message("ROCm is enabled.")
 elseif(USE_CUDA)
   set(AT_CUDA_ENABLED 1)
+  add_subdirectory(src/THC)
 else()
   message("disabling CUDA because USE_CUDA is set false")
   set(AT_CUDA_ENABLED 0)

aten/src/THC/CMakeLists.txt

@@ -0,0 +1,8 @@
+set(ATen_CUDA_INCLUDE ${ATen_CUDA_INCLUDE}
+  "${CMAKE_CURRENT_SOURCE_DIR}"
+PARENT_SCOPE)
+
+install(FILES
+          THCAtomics.cuh
+          THCDeviceUtils.cuh
+          DESTINATION "${ATEN_INSTALL_INCLUDE_SUBDIR}/THC")