anchor.diff:        ];
         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; {
  
positive.code:     boolWt
      head
      optional
      optionals
      optionalString
      splitString;
  
negative.code:   passthru = {
      inherit driverSearchPath version;
  
      srcVerification = fetchurl {
        failEarly = true;
        pgpsigUrls = map (n: "${n}.sig") src.urls;
  