Changes by: Jason J. Hickey (jyh at cs.caltech.edu)
Date: 2007-05-01 20:18:45 -0700 (Tue, 01 May 2007)
Revision: 10589
Log message:

      Backported the export hoisting.  This is something that never worked,
     but should have.
     
        Z. =
            x = 1
            f() =
                x = 2
                export
        Z.f()
        echo $(Z.x)
        # Prints "2"
     
     This works with arbitrary levels of nesting.