Merged revisions 77614-77616,77663 via svnmerge from

Merged revisions 77614-77616,77663 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk

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  r77614 | mark.dickinson | 2010-01-20 17:36:31 +0000 (Wed, 20 Jan 2010) | 5 lines

  Various dtoa.c cleanups.  1. Despagghetify _Py_dg_strtod parsing code
  and exit points.  2. Simplify bigcomp comparison loop.  3. Don't set
  ERANGE on _Py_dg_strtod underflow (it was set inconsistently anyway).
  4. Remove unused dsign field from BCinfo struct.
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  r77615 | mark.dickinson | 2010-01-20 18:02:41 +0000 (Wed, 20 Jan 2010) | 1 line

  Don't try to put a value into a NULL pointer.
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  r77616 | mark.dickinson | 2010-01-20 21:23:25 +0000 (Wed, 20 Jan 2010) | 1 line

  Additional explanatory comments for _Py_dg_strtod.
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  r77663 | mark.dickinson | 2010-01-21 17:02:53 +0000 (Thu, 21 Jan 2010) | 1 line

  Additional testcases for strtod.
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