Hello,
After seeing a lot of progress being made I went and investigated the sources a little more in detail and I've found: (you might want to skip towards to end because there is a slight problem)
Are covered by the GPL: swank-clisp.lisp bridge.el hyperspec.el slime.el swank-openmcl.lisp tree-widget.el
Are in the public domain: mkdist.sh present.lisp swank-abcl.lisp swank-allegro.lisp swank.asd swank-backend.lisp swank-cmucl.lisp swank-gray.lisp swank.lisp swank-lispworks.lisp swank-loader.lisp swank-sbcl.lisp swank-source-file-cache.lisp swank-source-path-parser.lisp test-all.sh test.sh doc/slime.texi doc/texinfo-tabulate.awk metering.lisp nregex.lisp
BSD-like license: swank-corman.lisp (I think will pose no problem)
Are without licenses: swank-ecl.lisp ChangeLog doc/Makefile HACKING NEWS PROBLEMS README
I think placing them into the public domain would also be easiest.
Then came a surprise, and I'm at a loss to explain how I missed it. My apologies for this.
The file xref.lisp is not PD or GPL (unlike my greps showed) but has a rather obnoxious license that says:
... ;;; o No fees or compensation are charged for use, copies, or ;;; access to this software. You may charge a nominal ;;; distribution fee for the physical act of transferring a ;;; copy, but you may not charge for the program itself.
This means you cannot put it into a distribution, and makes it DFSG unfree (even with the later clauses taken into consideration). To add insult to injury it has:
;;; o Any work distributed or published that in whole or in part ;;; contains or is a derivative of this software or any part ;;; thereof is subject to the terms of this agreement. The ;;; aggregation of another unrelated program with this software ;;; or its derivative on a volume of storage or distribution ;;; medium does not bring the other program under the scope ;;; of these terms.
As this file is part of slime, all of slime is under this agreement. Talk about a viral license ;-).
But then we have:
;;; o Permission is granted to manufacturers and distributors of ;;; lisp compilers and interpreters to include this software ;;; with their distribution.
So we can distribute it, if and only if we include also a lisp compiler? Strange, but it still makes it DFSG non-free.
What are our options for this?
Groetjes, Peter