Jerimy Katz is a Fedora developer. In a post to the fedora-devel-list he said:
Although I hate to do it, it looks like we're going to have to slip Fedora Core 5 test3 by a week. There is an ABI change in the gcc/glibc stack that requires a rebuild of the entire distribution. Given that, there is no way that we'll be able to make a freeze date of Monday. So, test3 will now freeze on Monday, 13 February with a release date of Monday, 20 February.
We'll adjust the final schedule sometime next week based on the progress of the rebuilding efforts.