multi-threaded top

Hi Craig,

Attached are 5 patches for newlib.  Interestingly, the smallest patch 
(#0002) is the most important one.

The others deal (mostly) with a multi-threading implementation for top. 
   Maybe someday I'll activate it by default, but for now it's just 
something to experiment with.

Thanks in advance for the push.

Regards,

Jim