dh_installchangelogs (debhelper-3.4.11) currently bails if one attempts to install a non-debian changelog to /usr/share/doc/<package>/changelog.gz in a debian-native package. Joey Hess has mentioned that various tools expect the changelog.gz for debian-native packages to parsable as debian-style changelogs. Given this expectation, one of two things should be done; either policy should be changed to explicitly allow multiple changelogs for debian-native packages, or explicitly disallow more than 1.
The current interpretation of it (section 13.8), for debian-native packages, reads as "if the package only has 1 changelog, put it in changelog.gz". This should be changed to something like: "If the package is a debian-native package, the changelog installed in /usr/share/doc/<package>/changelog.gz MUST be the debian changelog. If there are additional changelogs, they may be installed in the same directory, prefixed with 'changelog.'. For example, a single additional upstream changelog may be named 'changelog.Upstream.gz'. If upstream has changelogs on a per-directory basis, they may be named changelog.<subdirectory>.gz. Naming a changelog 'changelog.Debian.gz' is not suggested for debian-native packages, as it may confuse users." The exact quote from the current policy is: "If the package has only one changelog which is used both as the Debian changelog and the upstream one because there is no separate upstream maintainer then that changelog should usually be installed as /usr/share/doc/package/changelog.gz; if there is a separate upstream maintainer, but no upstream changelog, then the Debian changelog should still be called changelog.Debian.gz." -- "I think a lot of the basis of the open source movement comes from procrastinating students..." -- Andrew Tridgell <http://www.linux-mag.com/2001-07/tridgell_04.html>