anchor.diff:      boolWt
       head
       optional
  +    optionalAttrs
       optionals
       optionalString
       splitString;
  
positive.code:   passthru = {
      inherit driverSearchPath version;
  
      # opengl-dummy
      # XXX: this establishes interfaces for future use
      egl = true;
      egl-streams = true;  # To soon to tell where this will lead
      gbm = true;
      glesv1 = true;
      glesv2 = true;
      glx = true;
  
  
      srcVerification = fetchurl {
        failEarly = true;
        pgpsigUrls = map (n: "${n}.sig") src.urls;
  
negative.code:       ];
        inherit (src) urls outputHash outputHashAlgo;
      };
    } // optionalAttrs (buildConfig == "opengl-dummy") {
      # opengl-dummy
      # XXX: this establishes interfaces for future use
      egl = true;
      egl-streams = true;  # To soon to tell where this will lead
      gbm = true;
      glesv1 = true;
      glesv2 = true;
      glx = true;
    };
  
    meta = with lib; {
  