The latest installation for linux now uses cmake scripts. Still under development, but it works OK on my Pi4 under Raspbian Buster.
The cmake scripts includes the new kiss_fft/kiss_fft stuff which is used for the new scope spectrum trace
Have a look at the unix_prebuild.sh and unix_setup.sh scripts. At present MacOS is handled a little differently. On Raspbian I had also to build and install osmid binaries to app/server/native/osmid, to build the two erlang beam files from osc.elr and pi_server.erl using erlc, to add a soft link to ruby in /app/server/native/ruby/bin and to gem install aubio. Otherwise these two scripts prepared the whole build which was executed in the build folder they set up with cmake --build . --config All
You will notice that Sam Aaron has now moved many of other build scripts in Sonic Pi to an archive folder. The intention is to produce a unified scheme using cmake to build either for Windows Mac or Linux.
Things are still evolving and change fairly frequently, but looking along these lines above should get you on the way.