Implements getppid in the os module on Windows systems. The getppid 
function was only available on Unix like systems, this diff patch brings 
this functionality to Windows systems.  This function will return the 
parent process Id, upon error it raises a WindowsError. This differs 
from the Unix implementation that never fails.  Due to the way Windows 
returns the parent process Id, a never fail guarantee can not be made.  
This is a revision of a previous post.  The file Issue6394-1.diff 
contains the updated patches.