Commit af18f1dac0b5 ("scripts: start_build: create libpthread and
librt as well") added helper libs so that packages that try to find
these libs can do so.
%ci:no-build
Cava is an Audio Visualizer that can work together with MPD. It works
out of the Box if you enable "visulizer output" in MPD by either running
`mpc enable 3` or by enabling it in [7] in ncmpcpp.