[krbdev.mit.edu #7508] Indefinite FD polling

[Greg Hudson via RT]

If you can run a build with symbols so that you can get more information 
the next time you observe this, that will be helpful in tracking this 
down.  In particular:

* Which call site of service_fds() is spinning (line numbers in the stack 
trace will suffice)
* What are the contents of the selstate structure
* What are the contents of the conns list

Thanks.