The file torch/torch.h is not in the package.
I just downloaded the libtorch package from https://download.pytorch.org/libtorch/nightly/cu90/libtorch-win-shared-with-deps-latest.zip and when unzipping I find torch.h
in libtorch/include/torch/csrc/api/include/torch/torch.h. You have to set your include path to libtorch/include/torch/csrc/api/include/
or just use our CMake.