[torch] Add torch cpp cpu target for torch/csrc/api/src files (#87327)

Summary: Duplicating fbcode target `fbcode//caffe2:torch-cpp-cpu` target in xplat. In D40460749 our user wants to use `torch::kNearest` enum which is defined in `torch/csrc/api/src/enum.cpp`. Adding this target to support it.

Test Plan: Rely on CI

Differential Revision: D40532087

Pull Request resolved: https://github.com/pytorch/pytorch/pull/87327
Approved by: https://github.com/ezyang

buckbuild.bzl

@@ -22,6 +22,7 @@ load(
     "jit_core_headers",
     "jit_core_sources",
     "libtorch_profiler_sources",
+    "torch_cpp_srcs",
     "torch_mobile_tracer_sources",
 )
 load(
@@ -1368,6 +1369,19 @@ def define_buck_targets(
         ],
     )
 
+    pt_xplat_cxx_library(
+        name = "torch_cpp_cpu",
+        srcs = torch_cpp_srcs,
+        headers = native.glob(["torch/csrc/api/include/**/*.h"]) + ["torch/script.h"],
+        compiler_flags = get_pt_compiler_flags(),
+        exported_preprocessor_flags = get_pt_preprocessor_flags(),
+        visibility = ["PUBLIC"],
+        exported_deps = [
+            ":torch",
+            ":torch_mobile_deserialize_common",  # for torch/csrc/api/src/serialize/input-archive.cpp
+        ],
+    )
+
     pt_xplat_cxx_library(
         name = "torch_core",
         srcs = core_sources_full_mobile_no_backend_interface + [