anchor.diff:  
       boot.extraModulePackages =
         optional (cfg.videoDriver == "nvidia") kernelPackages.nvidia_x11 ++ 
  -      optional (cfg.videoDriver == "nvidiaLegacy") kernelPackages.nvidia_x11_legacy;
  +      optional (cfg.videoDriver == "nvidiaLegacy") kernelPackages.nvidia_x11_legacy ++
  +      optional (cfg.videoDriver == "vboxvideo") kernelPackages.virtualboxGuestAdditions;
   
       environment.etc = optionals cfg.exportConfiguration
         [ { source = "${configFile}";
  
positive.code:     openchrome = { modules = [ xorg.xf86videoopenchrome ]; };
      cirrus =     { modules = [ xorg.xf86videocirrus ]; };
      vmware =     { modules = [ xorg.xf86videovmware ]; };
    };
  
    videoDriver = cfg.videoDriver;
  
negative.code:       ]
        ++ optional (videoDriver == "nvidia") kernelPackages.nvidia_x11
        ++ optional (videoDriver == "nvidiaLegacy") kernelPackages.nvidia_x11_legacy;
        
      environment.systemPackages = config.environment.x11Packages;
      
      services.hal.packages = halConfigFiles;
  