Hi,

when doing a binNMU of fftw3 3.3.10-1 (found in bookworm), this falls
over because the package does a "chmod -R g-s ." from the clean rule.

This command fails on debian/changelog, because it isn't owned by
pbuilder/pbuilder (1234:1234), but by root, after the binNMU is added.

The fftw3 package is also slightly wrong here, but this also looks like
an oversight in pbuilder.

   Simon