anchor.diff:  let
     inherit (stdenv.lib)
       optional;
  +
  +  version = "1.0.21";
   in
  -
   stdenv.mkDerivation rec {
  -  name = "libusb-1.0.20";
  +  name = "libusb-${version}";
   
     src = fetchurl {
  -    url = "mirror://sourceforge/libusb/libusb-1.0/${name}/${name}.tar.bz2";
  -    multihash = "QmVhJXs3ZHHguFH9KbQuFNPeN4sePqMB6BUmgBQUHWZnWp";
  -    sha256 = "1zzp6hc7r7m3gl6zjbmzn92zkih4664cckaf49l1g5hapa8721fb";
  +    url = "https://github.com/libusb/libusb/releases/download/v${version}/"
  +      + "${name}.tar.bz2";
  +    sha256 = "7dce9cce9a81194b7065ee912bcd55eeffebab694ea403ffb91b67db66b1824b";
     };
   
     buildInputs = [
  
positive.code:   configureFlags = [
      "--disable-maintainer-mode"
      "--enable-udev"
      #"--enable-timerfd"
      "--enable-log"
      "--disable-debug-log"
  
negative.code:     "-lgcc_s"
    ];
  
    meta = with stdenv.lib; {
      description = "Userspace access to USB devices";
      homepage = http://www.libusb.info;
  