Thanks for taking time to look into this.
Yes, you need to have at least one playback target! JACK and Pulse are the most likely candidates on Linux. With the 1.7 release, this is probably a question of adjusting the defines in the prf/sv.prf file (it does use pkg-config to pick up what libraries are available, but presumably this has failed).
Ok I'm not very familiar with that, but as a workaround to get at least JACK output working I dug into it a bit and thought the problem might be jack 2, so I managed to compile by:
- installing jack 1 and libs
- compile SV
- re-install jack 2
The caveat is that in this way removing jack 1 pulls all packages (e.g. ardour and many other applications) which are marked to depend on it. So it is a good idea to take a note of the removed packages.
Interestingly sonic visualiser continues to work perfectly with jack 2.
The recently-released 1.8 has a different build system, using autoconf for these things, which may be worth a try. So far there is only a 32-bit Linux binary available for that, but hopefully I should be able to make a 64-bit one as well shortly.
Autoconf seems interesting and should make it easier to dig into the dependencies. As soon as I have the time I'll try to compile it and maybe give my feedback.