setup: drop the inaccessible `py2exehacked` code around distutils The comment heavily implies, and experimenting confirms, that there's no `sys.real_prefix` in a venv on Python3. I have no idea how the problems described would manifest, but nobody has complained for the several years of py3 releases build from a venv. The experimenting was done with 6.9.2 and the TortoiseHg build script.