Permission to use portions of the recent GNU Emacs Manual

[Robert J. Chassell]

   DOC strings and manual entries are material that are frequently
   copied between those differently licenced items.

Now I see what you are saying.  The legal question is, 

    when you are basing additions to a Texinfo manual on a large
    number of doc strings from functions, are the changes you are
    likely to make big enough so that the manual does not become a
    derivative work?

(Presumably, fair use means the issue is not relevant to a small
number of doc strings.  And the issue not relevant to additions that
are quite different.)

I don't know the legal answer.  Presuming that neither RMS nor anyone
else has thought of this, it becomes necessary to ask some people who
understand the laws in all the major countries of concern.  That is a
major undertaking.

My hunch is that a legally valid expectation is that any one's write
up will be sufficiently different, simply because he or she is trying
to write a document, not a doc string.  Put another way, only poorly
written documentation would be illegal....

But maybe not.  As for

  ... code snippets ...  [which include doc strings]

at the end of the node,
    (emacs)GNU Free Documentation License
says

    If your document contains nontrivial examples of program code, we
    recommend releasing these examples in parallel under your choice
    of free software license, such as the GNU General Public License,
    to permit their use in free software.

which handles this issue unless you are moving others' code into a
Texinfo manual without rewriting it more appropriately for a manual.
If my hunch is right, that would be no problem since it would be
reasonable to expect you to rewrite it suitably.  Otherwise, as far as
I can see, you have a reasonable point.

--
    Robert J. Chassell
    bob at rattlesnake.com                         GnuPG Key ID: 004B4AC8
    http://www.rattlesnake.com                  http://www.teak.cc