I mean dist-f15-override actually

I'd suggest using the self-service,
https://admin.fedoraproject.org/updates/override/

That doesn't work:
Error: Could not determine release for gcc-4.6.1-8.fc15 with tags ['dist-f15-updates-testing-pending']

(that package has been already in dist-f15-updates-testing, but got untagged because of negative karma, there is nothing wrong about the package though, just libtool needs to be rebuilt and added to the errata).

Oddly, the override worked... it's in the override tag and in the buildroot. (and causing other builds to fail).

Let us know when you are done with it so we can untag to allow people to build again.

I've in the mean time actually managed to koji tag-pkg it into dist-f15-updates-candidate and then the self-service worked and it seems to be gone from the override again. Thanks.