basewiki_brokenlinks.t fails when running dpkg-buildpackage in non-English environment : it greps for an (non-)error message that is i18n'd. This of course does not happen when building in a proper chroot environment... which happens to fail as well, for other reasons, but this will be for another bug.
LANG= on line 9 does not seem to do what it's supposed to, go figure.
I've never had to understand the Unix locales, so I randomly tried to replace
LANG= in basewiki_brokenlinks.t with :