No subject

hard.  I'm not at all an expert on the subject, but the 
confusion goes something like this:

Package `cool_tracker` requires `libjack0`

`libjack0` is supplied by Jack1 _and_ Jack2.  If you switch 
jackd's, you have to switch libjack0.  So, then you get 
something like:

    libjack0-jack1 (provides libjack0)
    libjack0-jack2 (provides libjack0)

Suppose user does:

    $ apt-get cool_tracker

Now, which one gets installed by default?

And when a someone packages `cool_tracker`

    $ gcc -o cool_tracker `pkg-config --cflags --libs jack` cool_tracker.c

Then cool_tracker has a link to /usr/lib/libjack.so.0

So... you have to make sure that the .deb package says it 
needs the virtual libjack0 package instead of libjack0-jack2 
(which is what the packager has installed).

THEN, you run into ABI issues between Jack1 and Jack2. 
Theoretically, there should be none -- but last I 
check, Jack2 is missing some of Jack1's symbols.

-gabriel