More Fedora mock breakage

[Tom Lane]

I'm getting a pile of these:

ERROR with rpm_check_debug vs depsolve:
rpmlib(PayloadIsXz) is needed by exim-4.69-12.fc12.x86_64
rpmlib(PayloadIsXz) is needed by crontabs-1.10-31.fc12.noarch
rpmlib(PayloadIsXz) is needed by logrotate-3.7.8-3.fc12.x86_64
rpmlib(PayloadIsXz) is needed by tar-2:1.22-6.fc12.x86_64
rpmlib(PayloadIsXz) is needed by openldap-2.4.16-2.fc12.x86_64
rpmlib(PayloadIsXz) is needed by ncurses-libs-5.7-3.20090207.fc12.x86_64
rpmlib(PayloadIsXz) is needed by grep-2.5.3-5.fc12.x86_64
rpmlib(PayloadIsXz) is needed by ncurses-base-5.7-3.20090207.fc12.x86_64
rpmlib(PayloadIsXz) is needed by gdbm-1.8.0-33.fc12.x86_64
rpmlib(PayloadIsXz) is needed by xz-4.999.8-0.8.beta.fc12.x86_64
rpmlib(PayloadIsXz) is needed by ustr-1.0.4-9.fc12.x86_64
...

while trying to build rawhide packages under mock.  Host is a fully
up2date Fedora 10 x86_64 system, selected mock config is
fedora-rawhide-x86_64.

What's especially curious is that it seems to work if I rm -rf
the contents of /var/lib/mock and /var/cache/mock first...
but I'm not eager to re-download all that stuff every time.

			regards, tom lane