[Build] Add COMMIT_SHA to caffe2::GetBuildOptions (pytorch#141313)

Using the same `tools/generate_torch_version.py` script

It's already available on Python level, but not on C++ one

Please note, that updating commit hash will force recompilation of less than 10 files according to
```
% touch caffe2/core/macros.h; ninja -d explain -j1 -v -n torch_python
ninja explain: output caffe2/torch/CMakeFiles/gen_torch_version doesn't exist
ninja explain: caffe2/torch/CMakeFiles/gen_torch_version is dirty
ninja explain: /Users/malfet/git/pytorch/pytorch/torch/version.py is dirty
ninja explain: output third_party/kineto/libkineto/CMakeFiles/libkineto_defs.bzl of phony edge with no inputs doesn't exist
ninja explain: third_party/kineto/libkineto/CMakeFiles/libkineto_defs.bzl is dirty
ninja explain: output caffe2/CMakeFiles/torch_cpu.dir/__/aten/src/ATen/Version.cpp.o older than most recent input /Users/malfet/git/pytorch/pytorch/build/caffe2/core/macros.h (1732301546390618881 vs 1732301802196214000)
ninja explain: caffe2/CMakeFiles/torch_cpu.dir/__/aten/src/ATen/Version.cpp.o is dirty
ninja explain: output caffe2/CMakeFiles/torch_cpu.dir/core/common.cc.o older than most recent input /Users/malfet/git/pytorch/pytorch/build/caffe2/core/macros.h (1732301546233600752 vs 1732301802196214000)
ninja explain: caffe2/CMakeFiles/torch_cpu.dir/core/common.cc.o is dirty
ninja explain: output caffe2/CMakeFiles/torch_cpu.dir/serialize/inline_container.cc.o older than most recent input /Users/malfet/git/pytorch/pytorch/build/caffe2/core/macros.h (1732301546651089243 vs 1732301802196214000)
ninja explain: caffe2/CMakeFiles/torch_cpu.dir/serialize/inline_container.cc.o is dirty
ninja explain: output caffe2/CMakeFiles/torch_cpu.dir/serialize/file_adapter.cc.o older than most recent input /Users/malfet/git/pytorch/pytorch/build/caffe2/core/macros.h (1732301546224176845 vs 1732301802196214000)
ninja explain: caffe2/CMakeFiles/torch_cpu.dir/serialize/file_adapter.cc.o is dirty
ninja explain: output caffe2/CMakeFiles/torch_cpu.dir/utils/threadpool/ThreadPool.cc.o older than most recent input /Users/malfet/git/pytorch/pytorch/build/caffe2/core/macros.h (1732301546464535054 vs 1732301802196214000)
ninja explain: caffe2/CMakeFiles/torch_cpu.dir/utils/threadpool/ThreadPool.cc.o is dirty
ninja explain: output caffe2/CMakeFiles/torch_cpu.dir/__/torch/csrc/jit/runtime/static/impl.cpp.o older than most recent input /Users/malfet/git/pytorch/pytorch/build/caffe2/core/macros.h (1732301550062608920 vs 1732301802196214000)
ninja explain: caffe2/CMakeFiles/torch_cpu.dir/__/torch/csrc/jit/runtime/static/impl.cpp.o is dirty
ninja explain: output caffe2/CMakeFiles/torch_cpu.dir/__/aten/src/ATen/mps/MPSFallback.mm.o older than most recent input /Users/malfet/git/pytorch/pytorch/build/caffe2/core/macros.h (1732301547538843492 vs 1732301802196214000)
ninja explain: caffe2/CMakeFiles/torch_cpu.dir/__/aten/src/ATen/mps/MPSFallback.mm.o is dirty
```

Differential Revision: [D66468257](https://our.internmc.facebook.com/intern/diff/D66468257)
Pull Request resolved: pytorch#141313
Approved by: https://github.com/ezyang

caffe2/core/macros.h.in

@@ -43,6 +43,7 @@
   {"CUDA_VERSION", "${CUDA_VERSION}"}, \
   {"ROCM_VERSION", "${ROCM_VERSION}"}, \
   {"USE_CUDNN", "${USE_CUDNN}"}, \
+  {"COMMIT_SHA", "${COMMIT_SHA}"}, \
   {"CUDNN_VERSION", "${CUDNN_VERSION}"}, \
   {"USE_NCCL", "${USE_NCCL}"}, \
   {"USE_MPI", "${USE_MPI}"}, \

cmake/Codegen.cmake

@@ -35,6 +35,13 @@ endfunction()
 
 ################################################################################
 
+# -- [ Deterine commit hash
+execute_process(
+    COMMAND "${Python_EXECUTABLE}" -c "from tools.generate_torch_version import get_sha;print(get_sha('.'), end='')"
+    OUTPUT_VARIABLE COMMIT_SHA
+    WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}/..
+)
+
 # ---[ Write the macros file
 configure_file(
     ${CMAKE_CURRENT_LIST_DIR}/../caffe2/core/macros.h.in