Patch requested for info.el

It appears that some releases of makeinfo, in particular 5.1, which
ships with RHEL7, have a small incompatibility with the way we (and
Emacs) read subfiles.  Although this problem doesn't arise in makeinfo
6, it would be good to fix it.  Fortunately Emacs has a fix, described
here (along with analysis of the problem):

  http://lists.gnu.org/archive/html/bug-texinfo/2013-04/msg00029.html

Could we have this done to our info.el, please?  Note that it does
_not_ break forward compatibility to do this, i.e it works with old
(4.13), middle-aged (5.1) and young (6.0) versions of makeinfo.

Thanks,

ht
-- 
       Henry S. Thompson, School of Informatics, University of Edinburgh
      10 Crichton Street, Edinburgh EH8 9AB, SCOTLAND -- (44) 131 650-4440
                Fax: (44) 131 650-4587, e-mail: [email protected]
                       URL: http://www.ltg.ed.ac.uk/~ht/
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