In principle I don't have a problem with the automatic generation of an
EXE (I assume it generates a shell script with no extension on Unix?)
but it should be done in such a way that the EXE is version-independent.
This is necessary to ensure that pure-python packages, when made into
bdist_wininst installers, continue to be version-independent. (At the
moment, distutils generates version-dependent bdist_wininst packages
*only* for C extensions. Setuptools generates version-dependent
installers all the time, which is a pain).

This may mean that a reimplementation is required, rather than copying
the setuptools code.