Another extended BSD licence :-/

[Simon Richter <sjr@debian.org>]

Hi,

I have been asked to provide packages for a small piece of software that
uses this licence:

    This software is provided 'as-is', without any express or implied
    warranty.  In no event will the authors be held liable for any damages
    arising from the use of this software.
    
    Permission is granted to anyone to use this software for any purpose,
    including commercial applications, and to alter it and redistribute it
    freely, subject to the following restrictions:
    
    1. The origin of this software must not be misrepresented; you must not
       claim that you wrote the original software. If you use this software
       in a product or c64-release, an acknowledgment in the product 
       documentation or credits would be appreciated. Or beer!
    2. Altered source versions must be plainly marked as such, and must not be
       misrepresented as being the original software.
    3. This notice may not be removed or altered from any source distribution.
    4. If you alter this software and release it, you must also provide the
       source. You may not turn this into yet-another-windows-only-c64-
       software. The software's platform independance and portability must
       be maintained, no x86-only assembly code (unless there's also a plain
       C version of it), no Windows-only API shit. If you violate this,
       pestilence shall come upon you, and DeeKay shall come to your house 
       and format your harddrive to install Linux. Your C64 will be
       confiscated and you will be forced to use a Sinclair Spectrum ZX81 
       to do all your coding - with its shitty membrane keyboard!

The first three paragraphs look like a BSD licence to me, paragraph four
is a personal rant from the authors. Apart from the obvious (remove
everything following "no x86-only assembly code..."), what else would be
needed to make this a valid licence suitable for inclusion into
non-free?

I can see:

 - it is not specified to whom you need to provide source
 - "You may not turn this..." would be implied in the next sentence
 - the bit about portability is pretty vague.

I'm going to try to convince the authors to use the GPL, but given their
aversion to OSS "politics" I'm not sure that will work. :/

   Simon