Blocked revisions 70479 via svnmerge

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  r70479 | mark.dickinson | 2009-03-20 15:51:55 +0000 (Fri, 20 Mar 2009) | 3 lines

  Issue #4258:  Use 30-bit digits for Python longs, on 64-bit platforms.
  Backport of r70459.
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