Parse the command line and check the arguments before build_deps() (#16914)
Summary:
This is needed to check for wrong arguments or --help options
before `build_deps()` is executed. Otherwise command line arguments
are not parsed and checked until `setup()` is run.
Fixes: #16707
Pull Request resolved: https://github.com/pytorch/pytorch/pull/16914
Differential Revision: D14041236
Pulled By: soumith
fbshipit-source-id: 41f635772ccf47f05114775d5a19ae04c495ab3b
