anchor.diff:  
     postInstall = ''
         wrapProgram $out/bin/obs \
  -        --prefix "LD_LIBRARY_PATH" : "${xorg.libX11.out}/lib:${vlc}/lib"
  +        --prefix "LD_LIBRARY_PATH" : "${xorg.libX11.out}/lib:${libvlc}/lib"
     '';
   
     postFixup = stdenv.lib.optionalString stdenv.isLinux ''
  
positive.code:     qtsvg
      speex
      x264
      vlc
      makeWrapper
      mbedtls
    ]
  
negative.code: , xorg
  , makeWrapper
  , pkgconfig
  , libvlc
  , mbedtls
  
  , scriptingSupport ? true
  