Hi,
I am the one who reported the bug against the gentoo ebuild.

AFAIK the following still holds true:
http://tech.groups.yahoo.com/group/firebird-support/message/67547

>> I haven't heard of any stability issues with running 32-bit Fb 1.5.3
>> on AMD64 Linux,
>
> Great, I have not experienced any and I have 2 different amd64 servers
> running Firebird in production now. One for over a year.

If you have installed the gentoo ebuild on amd64 then you don't run
32-bit Firebird! If you haven't experienced problems on your system you
can just unmask the package for yourself, where's the problem?

>
>> other than from people installing the non-NPTL x86
>> Superserver builds on OS versions that expect NPTL threading.
>
> Sure the nptl issue would be based on if the person compiled glibc with
> nptl or not on Gentoo. But that would be something we will deal with
> based on how they built the packages.
>
> Thanks for the confirmation, I will get 1.5.3 stabilized again on
> Gentoo. Also see about getting 1.5.4, and 2.0 packaged and in tree.
> Likely have to get help there from other Gentoo devs, or leave that up
> to the more skilled. Since it seems to require some build system
> patching to get it to compile.

I would still consider this a very bad idea, for both Gentoo and Firebird.

Michael