Repository: pytorch
Issue: build from scratch failed because of the expansion of macro
Labels: module: build,triaged

## 🐛 Bug

<!-- A clear and concise description of what the bug is. -->
build from source(commit:4bb5d33076ca79836a780df9473fdc96cad21a45) failed，and I commented the line 212 in anaconda3/include/python3.8/pyport.h，then made the compilation completed.
## To Reproduce

Steps to reproduce the behavior:
1、python setup.py install


<!-- If you have a code sample, error messages, stack traces, please provide it here as well -->
Here is CMake error stack.
[ 97%] Building CXX object caffe2/torch/CMakeFiles/torch_python.dir/csrc/jit/python/script_init.cpp.o
In file included from /home/david.wxy/anaconda3/include/python3.8/pyport.h:212:0,
                 from /home/david.wxy/anaconda3/include/python3.8/Python.h:63,
                 from /home/david.wxy/git/pytorch/torch/csrc/python_headers.h:10,
                 from /home/david.wxy/git/pytorch/torch/csrc/python_dimname.h:2,
                 from /home/david.wxy/git/pytorch/torch/csrc/python_dimname.cpp:1:
/home/david.wxy/git/pytorch/aten/src/ATen/core/aten_interned_strings.h:616:9: error: expected unqualified-id before ‘sizeof’
 _(aten, signbit) \
         ^
/home/david.wxy/git/pytorch/aten/src/ATen/core/aten_interned_strings.h:616:1: note: in expansion of macro ‘DEFINE_SYMBOL’
 _(aten, signbit) \
 ^
/home/david.wxy/git/pytorch/aten/src/ATen/core/interned_strings.h:246:3: note: in expansion of macro ‘FORALL_ATEN_BASE_SYMBOLS’
   FORALL_ATEN_BASE_SYMBOLS(_)        \
   ^
/home/david.wxy/git/pytorch/aten/src/ATen/core/interned_strings.h:473:1: note: in expansion of macro ‘FORALL_NS_SYMBOLS’
 FORALL_NS_SYMBOLS(DEFINE_SYMBOL)
 ^
/home/david.wxy/git/pytorch/aten/src/ATen/core/aten_interned_strings.h:616:9: error: expected ‘)’ before ‘sizeof’
 _(aten, signbit) \
         ^
/home/david.wxy/git/pytorch/aten/src/ATen/core/aten_interned_strings.h:616:1: note: in expansion of macro ‘DEFINE_SYMBOL’
 _(aten, signbit) \
 ^
/home/david.wxy/git/pytorch/aten/src/ATen/core/interned_strings.h:246:3: note: in expansion of macro ‘FORALL_ATEN_BASE_SYMBOLS’
   FORALL_ATEN_BASE_SYMBOLS(_)        \
   ^
/home/david.wxy/git/pytorch/aten/src/ATen/core/interned_strings.h:473:1: note: in expansion of macro ‘FORALL_NS_SYMBOLS’
 FORALL_NS_SYMBOLS(DEFINE_SYMBOL)
## Expected behavior

<!-- A clear and concise description of what you expected to happen. -->

## Environment

[pip3] numpy==1.18.5
[pip3] numpydoc==1.1.0
[pip3] torch==1.6.0
[conda] blas                      1.0                         mkl
[conda] mkl                       2020.1                      217
[conda] mkl-include               2020.2                      256
[conda] mkl-service               2.3.0            py38he904b0f_0
[conda] mkl_fft                   1.1.0            py38h23d657b_0
[conda] mkl_random                1.1.1            py38h0573a6f_0
[conda] numpy                     1.18.5           py38ha1c710e_0
[conda] numpy-base                1.18.5           py38hde5b4d6_0
[conda] numpydoc                  1.1.0                      py_0
[conda] torch                     1.6.0                    pypi_0    pypi

## Additional context

<!-- Add any other context about the problem here. -->


cc @malfet @seemethere @walterddr