anchor.diff:      libpng12
       libusb
       pango
  +    udev
       xorg.libSM
       xorg.libX11
       xorg.libXext
       xorg.libXft
       xorg.libXinerama
  +    xorg.libXxf86vm
       zlib
     ];
     teensy_architecture =
  
positive.code: , withGui ? false, gtk2 ? null, withTeensyduino ? false
    /* Packages needed for Teensyduino */
  , upx, fontconfig, xorg, gcc
  , atk, glib, pango, gdk-pixbuf, libpng12, expat, freetype,
  }:
  
  assert withGui -> gtk2 != null;
  
negative.code: 
    teensy_libpath = stdenv.lib.makeLibraryPath [
      atk
      cairo
      expat
      fontconfig
      freetype
  