Bug#251885: ITP: cgal -- C++ library for computational geometry

[Joachim Reichel <joachim.reichel@gmx.de>]

Hi,

> If the two licenses only applied to different libraries that linked to
> each other, they would be compatible, because the scope of the LGPL
> deliberately stops at the library boundary.  However, the LGPL requires
> that all code which directly incorporates LGPLed code be LGPLed.
> [...]
> So any "work based on the library" must be licensed under the LGPL.
> Since the QPL is not compatible with the LGPL, the entire work is
> non-distributable.

So what are the options for upstream?

a) Relicense the code in a way that the work is redistributable, if 
possible DFSG-free.

b) Split the library in (at least) two libraries, one (or more) for the 
LGPL code and one (or more) for the QPL code. (By "splitting", I mean 
creating two (or more) static/dynmaic libraries, not splitting the 
package itself.)

c) What about clause 7 of the LGPL:

>   7. You may place library facilities that are a work based on the
> Library side-by-side in a single library together with other library
> facilities not covered by this License, and distribute such a combined
> library, provided that the separate distribution of the work based on
> the Library and of the other library facilities is otherwise
> permitted, and provided that you do these two things:
>
>     a) Accompany the combined library with a copy of the same work
>     based on the Library, uncombined with any other library
>     facilities.  This must be distributed under the terms of the
>     Sections above.
>
>     b) Give prominent notice with the combined library of the fact
>     that part of it is a work based on the Library, and explaining
>     where to find the accompanying uncombined form of the same work.

For clarification, as I understand it:
"Library" = LGPL-part of the code
"library" = the dynamic/static library (including QPL code)

Would this be another option? Is there a piece of software that actually 
uses this clause?

d) What about an exception with respect to clause 2c) of the LGPL? 
Something similar like the GPL-waiver for libssl? This would also be an 
option, right?

Regards,
  Joachim