Re: How to avoid a "basic" single quote being replaced by a "curvy" one?

[Karl Berry]

Thanks for updating your Texinfo, but doing that does not necessarily
update texinfo.tex.  And apparently it did not in your case -- at least,
that would explain why the command is not defined.

To repeat, please try getting the current version from
http://ftpmirror.gnu.org/texinfo/texinfo.tex.  You can put in the
directory with the document.

pdftex, pdfetex, and pdfetexk are all the same thing.

    This is pdfeTeXk, Version 3.141592-1.21a-2.2 (Web2C 7.5.4)

It has nothing to do with the problem, but that is almost ten years old.
Pretty impressive :).

Best,
Karl