This fixes a problem sgran saw on alioth. Apparently nss-db sets errno to
ENOENT as a side effect trying to read an optional file, but succeeds
anyway. Then, somehow, errno remains set across the library calls made by
$).
So unset it first as a workaround; there's probably a nss-db, libc, and/or
perl bug underneath.
to be created owned by some group other than the default. Useful
then there's a shared repository with access controlled by a group,
to let ikiwiki run setgid to that group.
* ikiwiki-mass-rebuild: Run build with the user in all their groups.