Clang 9 and GCC 9 Support (#35835)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/35835
Make compilable with Clang 9 and GCC 9.
Test Plan: Compile with Clang 9 and GCC 9
Differential Revision: D20800182
fbshipit-source-id: dd9474640270de0ad6392641513a7f2fa970d6e3
