libc6 packages not in gcc4 "Packages" list

[Pavel Jurus <jurus@cs.cas.cz>]

I wanted to upgrade one of my computers using this /etc/apt/sources.list

"deb http://debian-ppc64.alioth.debian.org/gcc4 unstable main contrib
non-free"

Problem is that libc6 is non-upgradable because it missing (together
with other packages created from glibc source package) in Packages file.
Looking at http://debian-ppc64.alioth.debian.org/gcc4/pool/main/g/glibc/
however shows libc6_2.3.5-1_amd64.deb which is probably the needed
package. What's the problem with Packages file and how can I solve/work
around it?

Pavel Jurus