./configure problems on Fedora Core 8

I've asked on the Fedora Forums and the postgres IRC channel but haven't
received any feedback. I'm guessing there's just a library I'm missing
and I've tried this in 8.1.x, 8.2.6 and now 8.3.0 with the same result
so at least that's consistent. But when I do a './configure
--enable-thread-safety', it eventually bombs out saying:

...
checking for sgmlspl... sgmlspl
checking thread safety of required library functions... no
configure: error: thread test program failed
This platform is not thread-safe. Check the file 'config.log'for the
exact reason.

Upon checking the config.log, it says:

| #define MEMSET_LOOP_LIMIT 1024
| /* end confdefs.h. */
| #include "./src/test/thread/thread_test.c"
configure:22450: result: no
configure:22459: error: thread test program failed
This platform is not thread-safe. Check the file 'config.log'for the
exact reason.

Google searches show some posts where there have been instances where
thread_test.c doesn't actually exist but this isn't the case here. This
completes successfully on an old and obsolete FC4 system so I think it's
just that I'm missing a particular safe thread library or something.
Can anyone point me in the right direction?

Thanks!

Carlos