anchor.diff:    '';
   
     configurePhase = ''
  -    qmake CONFIG+="acs_alsa acs_jack" fmit.pro
  +    qmake \
  +      CONFIG+=${stdenv.lib.optionalString alsaSupport "acs_alsa"} \
  +      CONFIG+=${stdenv.lib.optionalString jackSupport "acs_jack"} \
  +      fmit.pro
     '';
   
     enableParallelBuilding = true;
  
positive.code:     owner = "gillesdegottex";
    };
  
    buildInputs = [ alsaLib fftw freeglut libjack2 qt5Full ];
  
    postPatch = ''
      substituteInPlace fmit.pro --replace '$$FMITVERSIONGITPRO' '${version}'
  
negative.code: # FIXME: upgrading qt5Full (Qt 5.3) to qt5.{base,multimedia} (Qt 5.4) breaks
  # the default Qt audio capture source!
  { stdenv, fetchFromGitHub, fftw, freeglut, qt5Full
  , alsaSupport ? false, alsaLib ? null
  , jackSupport ? false, libjack2 ? null }:
  
  assert alsaSupport -> alsaLib != null;
  assert jackSupport -> libjack2 != null;
  
  let version = "1.0.5"; in
  stdenv.mkDerivation {
  