Soft/hard dependency requirements post 2.8 - input, please

[Matěj Laitl]

On 29. 7. 2013 Myriam Schweingruber wrote:
> with the GSoC projects we discovered a few dependency requirements
> that will be necessary.
> 
> libcdio 0.90

This is usually fine, the distros package the libraries *for us* 
(applications), not for themselves, so if we declare the dependency in advance 
and communicate it well, it is okay.

However, I've heard that libcdio 0.90 has changed the API wrt 0.83. (0.83 
being common is distros today) Sam/Tatjana, please answer the following 
decision tree:

* Is 0.90 API backward compatible with 0.83 one? (meaning that apps written
  against 0.83 compile & work fine with 0.90 without porting)
a) Yes -> everything is fine, distros can compile all apps against 0.90 in
   their release after Amarok 2.9 (14.04 etc.)
b) No ->
   * Can cdio 0.83 and 0.90 coexist on the same system without significant
     effort?
   ba) Yes -> distros can just ship both
   bb) No ->
       * Are other apps depending on cdio 0.83 (i.e. ffmpeg, mplayer, ...)
         being ported to 0.90? Are any patches floating around?
       bba) Yes -> we need to coordinate with them to release versions
            depending on 0.90 at roughly the same time.
       bbb) No -> we might have a problem. Are the 0.83/0.90 changes
            significant?

	Matěj