Phonon 4 Qt 5 support

[Harald Sitter]

Yesterday Kevin Ottens and I ended up discussing Phonon 4 for Qt 5 on IRC...

Let me first recap what we discussed in randa though:
1. phonon five will have a simpler but similar api (no media graph)
2. as the proposed api looks right now it is close enough to phonon 4
to be jolly easy to port for everyone not using media graph stuff
3. to allow application developers a quick transition to qt 5 we will
provide a phonon 4 release that builds with qt 5

Now, looking at the proposed patches for qt 5 compatibility I do not
feel entirely comfortable introducing >50% of those into regular
phonon4. Instead we will have a different tarball and different
library to allow phonon4, phonon4support and phonon5 apps to be
installed on one system. This is of course very much in line with
point number 3 from randa. phonon4support will be in an own repository
(as ervin wants us to be release managed by kde? lol? :P) and
technically speaking that repo will contain a minimal changset onto of
the regular 4.7 branch (once created) that is required to make phonon4
work with qt5.

What remains to be decided is just how much we want to support
phonon4support deployments. I personally would like to openly
discourage deployment of software using the support library. In
particular any issue that is not reproduced with phonon4/qt4 and not
clearly a critical compat change WRT qt5 should probably be considered
a non-issue. The obvious rationale is that we'd otherwise have to
support 3 more or less different libraries for some period after
release of phonon5 (seeing as we will probably want to support phonon4
until all our major clients have switched to phonon5). So merging
phonon4/qt4 and phonon4/qt5 into one support target seems like a wise
choice to me.

And while I am on that topic... 4.7 will be the last feature release
before 5.0 and after it's release we may want to reduce overall
support for the 4.x series (e.g. only cirtical bug fixes that cannot
easily be worked around or something).

HS