anchor.diff:  
     hasXlibs = xlibs != null;
   
  -  optLibcap = if libOnly then null else shouldUsePkg libcap;
  +  optLibcap = shouldUsePkg libcap;
     hasCaps = optLibcap != null || stdenv.isFreeBSD; # Built-in on FreeBSD
   
     optOss = if libOnly then null else shouldUsePkg oss;
  
positive.code:   '';
  
    configureFlags = [
      "--localstatedir=/var"
      "--sysconfdir=/etc"
  
      (mkEnable false                   "atomic-arm-memory-barrier"  null)         # TODO: Enable on armv8
      (mkEnable false                   "neon-opt"                   null)         # TODO: Enable on armv8
      (mkEnable hasXlibs                "x11"                        null)
  
negative.code: 
      optLibcap valgrind optOss optCoreaudio optAlsaLib optEsound optGlib
      optGtk3 optGconf optAvahi optLibjack2 optLibasyncns optLirc optDbus optUdev
      optOpenssl optFftw optSpeexdsp optSystemd optWebrtc-audio-processing
    ] ++ stdenv.lib.optionals hasXlibs (with xlibs; [
        libX11 libxcb libICE libSM libXtst xextproto libXi
      ]) ++ stdenv.lib.optionals (optBluez5 != null) [ optBluez5 optSbc ];
  