[help-texinfo] How fix (non-fatal) error by producing .fo (by fop) from .docbook from .texi about missing entities?

[Oleksandr Gavenko]

I get cedet.texi from GNU Emacs distro, fix include issue and produce 
.docbook:

  $ makeinfo --enable-encoding --docbook -o cedet.docbook cedet.texi
  $ xsltproc --nonet --stringparam use.extensions 0 --output cedet.fo \
     /cygdrive/c/opt/docbook-xsl-1.76.1/fo/docbook.xsl cedet.docbook
...
cedet.docbook:14: parser error : Entity 'copy' not defined
      <para>Copyright &copy; 2007, 2008, 2009, 2010 Eric M. Ludlam</para>
                            ^
cedet.docbook:21: parser error : Entity 'ldquo' not defined
license is included in the section entitled &ldquo;GNU Free Documentation
                                                   ^
cedet.docbook:22: parser error : Entity 'rdquo' not defined
License&rdquo;.</para>
...

I checkout latest (??) DocBook schema from

  http://www.oasis-open.org/docbook/rng/4.5b1/

and:

  $ grep ldquo *.rnc || echo nothing found
nothing found

Why 'makeinfo' add

  &copy; &ldquo; &rdquo;

if DocBook spec don't include this entities?

Report a bug?