Code:
On Linux, plug-ins can be added to:
~/.audacity-files/plug-ins
/usr/share/audacity/plug-ins
/usr/lib/ladspa/plug-ins
/usr/local/share/audacity/plug-ins or
/usr/local/lib/ladspa/plug-ins
I don't see /usr/lib64
anywhere in here.
Perhaps linking /usr/lib64/ladspa to one of the recommended directories Audacity will look in. If perhaps, the /usr/lib/ladspa/plug-ins directory don't exist, link it with command:
ln -s /usr/lib64/ladspa /usr/lib/ladspa/plug-ins. The /usr/lib/ladspa directory needs to exist, create it if not present.
If it's just the autotalent.so file that needs to be in a valid plugin directory, put a copy of it there.