py3: add b'' to some setup.py strings for Windows These were things found trying to do `make PYTHON="py -3" local`. The following is dumped out, before dying while compiling the C extensions: C:\Program Files\Python37\lib\site-packages\setuptools\dist.py:406: UserWarning: The version specified (b'4.7.1') is an invalid version, this may not work as expected with newer versions of setuptools, pip, and PyPI. Please see PEP 440 for more details. "details." % self.metadata.version running build_py byte-compiling .\mercurial\thirdparty\concurrent\futures\_base.py to _base.cpython-37.pyc File "mercurial\thirdparty\concurrent\futures\_base.py", line 416 raise exception_type, self._exception, self._traceback ^ SyntaxError: invalid syntax # skip-blame since these are just converting to bytes literals