> Right, but the point is the behavior, not the specific license.  CLISP
> was barely using readline (just an unnecessary dress up of the UI) and
> even after the maintainer offered to repackage CLISP not to use it,
> RMS still wanted CLISP to be GPL'ed because it *could* be used with
> readline.

Actually, I do believe that he had no right to do so.  But there are 
many things to consider:

1) at the time, the GPL was very new (1991) and a precedent of its 
validity was badly needed;

2) the LGPL did not even exist; the LGPLv3 instead explicitly talks 
about subclassing, saying that it does not consitute creating a 
derivative work.

3) even the legal precedents for reverse-engineering of interfaces were 
not well established.  Today there are readline implementations under 
BSD license, and RMS never went against them.

Paolo