python-version-conflict for py-setuptools?

[Oliver Gould <ver%olix0r.net@localhost>]

It seems that I am unable to to install both py25-setuptools and
py26-setuptools on the same system.  Since py-setuptools is required to
install a plethora of Python packages, this is a rather severe blocker
to running more than one version of Python on a single system.

I'm seeing the following:
> $ grep PYTHON /etc/mk,conf
> PYTHON_VERSION_DEFAULT?= 26
> $ env PYTHON_VERSION_DEFAULT=25 make package
> => Bootstrap dependency digest>=20010302: found digest-20080510
> ===> Checking for vulnerabilities in py25-setuptools-0.6c9nb1
> ===> Installing for py25-setuptools-0.6c9nb1
> => Becoming ``root'' to make su-install-all (/usr/pkg/bin/sudo)
> Password:
> ERROR: py26-setuptools-0.6c9 is already installed - perhaps an older version?
> ERROR: If so, you may use either of:
> ERROR:     - "pkg_delete py26-setuptools-0.6c9" and "/usr/bin/make reinstall"
> ERROR:       to upgrade properly
> ERROR:     - "/usr/bin/make update" to rebuild the package and all
> ERROR:       of its dependencies
> ERROR:     - "/usr/bin/make replace" to replace only the package without
> ERROR:       re-linking dependencies, risking various problems.
> *** Error code 1
> 
> Stop.
> make: stopped in /home/netbsd/pkgsrc/devel/py-setuptools
> *** Error code 1
> 
> Stop.
> make: stopped in /home/netbsd/pkgsrc/devel/py-setuptools
> *** Error code 1
> 
> Stop.
> make: stopped in /home/netbsd/pkgsrc/devel/py-setuptools

Joerg, do you have any thoughts on how to resolve this conflict?  If
not, I'll probably start tearing at the Makefiles...

Regards,
  - Oliver