Hi Antonio,
To be fair the INSTALL file does say this:
It assumes you have the supercollider header include files located in:
/usr/include/SuperCollider/
If you have them in another location:
sc3-plugins/build/$ cmake -DSC_PATH=/usr/local/include/SuperCollider/ ..
or:
sc3-plugins/build/$ cmake -DSC_PATH=/path/to/sc3source/ ..
However it's one of those things that kind of assumes some knowledge of C++ and building on linux. I think they're assuming if you're compiling the SC3 plugins you're probably familiar with the various installation locations in a given linux distribution or how to know where and what to look for. It seems like building these plugins is giving many people trouble (I've seen many posts like these on the list) so maybe a more general help page on the
supercollider.github.io site or in the documentation for general building might be good? Does this exist? I dunno, however I'm happy to hear you have it working now. best,