With current trunk, after a make distclean; ./configure; make install
sequence, I get the following error:

[...]
# Substitution happens here, as the completely-expanded BINDIR
# is not available in configure
sed -e "s,@EXENAME@,/usr/local/bin/python2.7," < ./Misc/python-config.in
>python-config
/usr/bin/install -c python-config /usr/local/bin/python2.7-config
rm python-config
./python -E ./setup.py install \
                --prefix=/usr/local \
                --install-scripts=/usr/local/bin \
                --install-platlib=/usr/local/lib/python2.7/lib-dynload \
                --root=/
running install
error: must supply either home or prefix/exec-prefix -- not both
make: *** [sharedinstall] Error 1

works for me under MacOS X, I am trying now under debian

Benjamin can't reproduce it either.  Must be something weird in my
environment, so I'm lowering the priority.

Ok.

I confirm it works fine on a standard debian as well

I can see that 'self.home' is '~' when that error message is generated,
but I can't figure out where self.home gets set.  Any clues you can give me?

I figured it out.  It turns out that a while back I created a
.pydistutils.cfg file and put home in there.

There is a bug here, of some sort.  Either the .pydistutils.cfg file's
install clause should override the default --prefix somehow, or the
error message should indicate where the setting for 'home' and
'--prefix' came from to enable the user to debug the configuration.  In
the latter case there would also need to be a way to explicitly tell
either make install or configure to ignore .pydistutils.cfg.  In the
former case, an explicit --prefix passed to configure would need to
override .pydistutils.cfg.

Or perhaps there's some other solution I'm not seeing at the moment.

See #4655.  (Not sure which one is the superseder.)