Bug#183860: RMS's comment on this bug is mostly irrelevant. :-/

[Nathanael Nerode <neroden@twcny.rr.com>]

Attempt to clarify again:

The issue is entirely about generated files which contain elements of a 
GFDL'ed texinfo file *and* elements of the GPL'ed texinfo.tex; such 
files are presumably derivative works of both, but that means they can't 
be distributed.

GCC actually hit this already; I believe we ended up with a plan to 
switch to a differently-licensed replacement for texinfo.tex, though I 
think it hasn't been implemented yet.  (Neither have many other license 
problems at GCC.  :-P)