It doesn't work either, texinfo.tex seems to be a moving target and it
always causes headaches.
I am depressed to hear you say so. Yes, it is updated frequently, but
we (Oleg and I) try very hard to keep it compatible.
The particular incompatibility introduced in the TeX system regarding
the \pdfoutput test was highly unfortunate IMHO, but there's no use
discussing that again.
Anyway, Anton, if there are problems with gforth.texi with the current
texinfo.tex (ftp://tug.org/tex/texinfo.tex), please report them to
bug-texinfo ...
Best,
Karl