[kde-community] Qt Licence change in Licensing Policy

[Jonathan Riddell]

With the change in Qt licencing from LGPL 2.1 to LGPL 2.1/3/GPL 2 or
LGPL 3/GPL 2 we can consider getting rid of the clause in our
licensing policy which stops copying Qt code into KDE Platform.

"Note: code may not be copied from Qt into KDE Platform as Qt is LGPL 2.1 only which would prevent it being used under LGPL 3 "

I suggest replacing it with this:

"Note: when copying code from Qt into KDE Platform file you must
include the full Qt licence header in the header of these files and
you must name each of these files in COPYING-QT along with the
relevant LGPL licences in the root of the source tree. Note that most
Qt modules are LGPL 2.1/ 3 but newer ones may be LGPL 3 + GPL 2 and
this will affect the overall licensing of the module. This can only be
done with Qt 5.4 or later as ealier versions had more restrictive
licences. "

I think any files with Qt code in them need to be named so we can
easily keep track of them as it will cause problems when LGPL 4 comes
out and Qt hasn't yet changed to it.

Or this may be too faffy for too little gain and we should just keep not allowing Qt code in KDE Platform.

Jonathan