Dear Maintainer,

dpkg 1.22.21ubuntu6 in Ubuntu set `--package-metadata` directly in
`LDFLAGS` (see Launchpad bug #2071468) which requires reading
`debian/changelog`. The autopkgtest fails due to having this warning:

```
dpkg-buildflags: warning: debian/changelog not found. Not setting ELF package metadata parameter.
```

In Ubuntu, the attached patch was applied to achieve the following:

So we copy `debian/changelog` into the working directory on Ubuntu.

  * autopkgtest: copy debian/changelog for ELF package metadata (LP: #2134532)


Thanks for considering the patch.