anchor.diff:      #"--${boolEn (libcdio != null)}-libcdio"
       /**/"--disable-libcdio"
       /**/(fflag "--disable-libcodec2" "4.0")
  +    /**/(fflag "--disable-libdav1d" "4.1")
       /**/(fflag "--disable-libdavs2" "4.1")
       "--${boolEn (
         libdc1394 != null
  
positive.code:     "--${boolEn (libgcrypt != null)}-gcrypt"
      "--${boolEn (gmp != null)}-gmp"
      "--${boolEn (gnutls != null)}-gnutls"
      (fflag "--${boolEn (aomedia != null)}-libaom" "4.0")
      "--${boolEn (stdenv.cc.libc != null)}-iconv"
      (deprfflag "--${boolEn (jack2_lib != null)}-jack" null "3.4")
      "--${boolEn (jni != null)}-jni"
      "--${boolEn (ladspa-sdk != null)}-ladspa"
      "--${boolEn (libass != null)}-libass"
      "--${boolEn (libbluray != null)}-libbluray"
      "--${boolEn (libbs2b != null)}-libbs2b"
  
negative.code:     };
      "9.9" = {  # Git
        fetchzipversion = 6;
        version = "2019.02.14";
        rev = "9e1e5213933dfed529f0cecac7304236a786177e";
        sha256 = "daeb1af827a9a3331a99efb11bf57ee06dcc65eaa4fb0438469caba52d7f2620";
      };
    };
    source = sources."${channel}";
  