could zombie pipes be created when apps like tar do not explicitely
close
stdout/stderr before exiting?
In the case I had to debug the autorelease pool wasn't drained when
the main app was in the background. The NSTasks were not released and
the assiciated NSPipes neither, which lead to filehandle exhaustion
after processing around 100 files with four subtaks รก 2 handles.
Debugged with lsof and ObjectAlloc, the fix I described AFAIR here.
