I'm trying to use fid_abs, and need pool object
I have simply downloaded it first, but it freezes Pure Data.
This problem is often encountered in some linux distrib (in my case Ubuntu Studio 8.04).
So, I compiled pool.pd_linux with flext.
Compilation and installation proceed correctly, but after configuring PD to load pool on startup, I have this error when I open a patch using pool :

tried /usr/lib/pd/extra/pool.pd_linux and succeeded
/usr/lib/pd/extra/pool.pd_linux: /usr/lib/pd/extra/pool.pd_linux: undefined symbol: __sync_fetch_and_add_4

and then :

pool fid_abs
... couldn't create

I don't really understand this message, and where the problem comes from.
I'm a beginner with Pd and object compilation, so I'm not sure I did it correctly. I join my flext config file, which may be wrong?