anchor.diff:      sha256 = "1s9idx2miwk178sa731ig9r4fzx4gy1q8xazfqyd7q4lfd70s1cy";
     };
   
  +  asterisk-opus = fetchFromGitHub {
  +    owner = "traud";
  +    repo = "asterisk-opus";
  +    # No releases, points to master as of 2022-04-06
  +    rev = "a959f072d3f364be983dd27e6e250b038aaef747";
  +    sha256 = "sha256-CASlTvTahOg9D5jccF/IN10LP/U8rRy9BFCSaHGQfCw=";
  +  };
  +
     # auto-generated by update.py
     versions = lib.mapAttrs (_: {version, sha256}: common {
       inherit version sha256;
  
positive.code:     buildInputs = [ jansson libedit libxml2 libxslt ncurses openssl sqlite
                      dmidecode libuuid newt
                      lua speex
                      srtp wget curl iksemel ];
      nativeBuildInputs = [ util-linux pkg-config ];
  
      patches = [
        # We want the Makefile to install the default /var skeleton
  
negative.code:       ${lib.optionalString (externals ? "addons/mp3") "bash contrib/scripts/get_mp3_source.sh || true"}
  
        chmod -w externals_cache
        ${lib.optionalString withOpus ''
          cp ${asterisk-opus}/include/asterisk/* ./include/asterisk
          cp ${asterisk-opus}/codecs/* ./codecs
          cp ${asterisk-opus}/formats/* ./formats
        ''}
        ./bootstrap.sh
      '';
  
      configureFlags = [
  