On Tue, 22 Mar 2005, Alfred M. Szmidt wrote:
Including code from non-free libraries will make your package non-free.
Not true. The result would be illegal, not non-free.
The license of the library might permit one to use code from it, but still might make it non-free in the sense of the GNU GPL. For example, it might restrict the terms of redistribution.
For it to be legal the whole work has to be licensed under the GNU GPL.
I think this might not be quite correct, depending on what is meant by "the whole work". There are licenses considered by the FSF to be compatible with the GNU GPL. To be absolutely sure about licensing matters, it's always best to ask the people at the FSF who specialize in them.
Once can add a special execption to the GPLed library so one allows for non-free libraries to use it, see the GPL FAQ "How can I allow linking of proprietary modules with my GPL-covered library under a controlled interface only?"
I don't see any why one couldn't make it possible for one's code to be linkable to non-free libraries, as long as the interface to those libraries is either free or non-copyrightable. However, I don't think doing so would be a good idea.
Laurence Finston