anchor.diff:    mesonFlags = [
       "-Dexamples=disabled" # requires many dependencies and probably not useful for our users
       "-Ddoc=disabled" # `hotdoc` not packaged in nixpkgs as of writing
  -    "-Dqt5=disabled" # not clear as of writing how to correctly pass in the required qt5 deps
  +  ] ++ optionals (!qt5Support) [
  +    "-Dqt5=disabled"
     ] ++ optionals (!gtkSupport) [
       "-Dgtk3=disabled"
     ] ++ optionals (!enableJack) [
  
positive.code:   ] ++ optionals gtkSupport [
      # for gtksink
      gtk3
    ] ++ optionals stdenv.isDarwin [
      darwin.apple_sdk.frameworks.Cocoa
    ] ++ optionals stdenv.isLinux [
      libv4l
  
negative.code: , mpg123
  , twolame
  , gtkSupport ? false, gtk3 ? null
  , qt5Support ? false, qt5 ? null
  , raspiCameraSupport ? false, libraspberrypi ? null
  , enableJack ? true, libjack2
  , libXdamage
  