anchor.diff:      "--${boolWt (xorg != null)}-xfixes"
       "--${boolWt (xorg != null)}-xinput"
       "--${boolWt (xorg != null)}-xim"
  -    "--${boolWt (mesa != null)}-opengl"
  +    "--${boolWt (opengl-dummy != null)}-opengl"
     ];
   
     doCheck = true;
  
positive.code: , libsm
  , libtiff
  , libx11
  , mesa
  , xorg
  , zlib
  }:
  
negative.code:     bzip2
      fontconfig
      freetype
      libice
      libjpeg
      libpng
      libsm
      libtiff
      libx11
      opengl-dummy
      xorg.libXext
      xorg.libXcursor
      xorg.libXft
  