[OE-core] License of xz

[Anders Darander]

I've recently started to look into building internal images with 
INCOMPATIBLE_LICENSE = "GPLv3"

Sofar, I've mainly identified one issue, which is with the xz-package.
(This is currently a dependency of systemd).

xz sets LICENSE = "GPLv2+ & GPLv3+ & LGPLv2.1+"

If the info in COPYING from xz sources is correct, I guess that we
should be able to remove GPLv3 from the target packages. Would you agree
with that, or have I overlooked something?

If my interpretation is correct, I'll try to find more time to look into
the actual source files a bit more closely.


/Anders


Extract from COPYING:
 

XZ Utils Licensing
==================

    Different licenses apply to different files in this package. Here
    is a rough summary of which licenses apply to which parts of this
    package (but check the individual files to be sure!):

      - liblzma is in the public domain.

      - xz, xzdec, and lzmadec command line tools are in the public
        domain unless GNU getopt_long had to be compiled and linked
        in from the lib directory. The getopt_long code is under
        GNU LGPLv2.1+.

      - The scripts to grep, diff, and view compressed files have been
        adapted from gzip. These scripts and their documentation are
        under GNU GPLv2+.

      - All the documentation in the doc directory and most of the
        XZ Utils specific documentation files in other directories
        are in the public domain.

      - Translated messages are in the public domain.

      - The build system contains public domain files, and files that
        are under GNU GPLv2+ or GNU GPLv3+. None of these files end up
        in the binaries being built.

      - Test files and test code in the tests directory, and debugging
        utilities in the debug directory are in the public domain.

      - The extra directory may contain public domain files, and files
        that are under various free software licenses.


-- 
Anders Darander
ChargeStorm AB / eStorm AB