anchor.diff:      "--${boolEn (gmp != null)}-gmp"
       "--${boolEn (gnutls != null)}-gnutls"
       "--${boolEn (stdenv.cc.libc != null)}-iconv"
  -    "--${boolEn (jack2_lib != null)}-jack"
  +    (deprfflag "--${boolEn (jack2_lib != null)}-jack" null "3.4")
       "--${boolEn (jni != null)}-jni"
       "--${boolEn (ladspa-sdk != null)}-ladspa"
       "--${boolEn (libass != null)}-libass"
  
positive.code:       sha256 = "aeee06e4d8b18d852c61ebbfe5e1bb7014b1e118e8728c1c2115f91e51bffbef";
      };
      "9.9" = { # Git
        version = "2017.10.18";
        rev = "f4090940bd3024e69d236257d327f11d1e496229";
        sha256 = "bb1105f0d8a65a0d7c85e9ac709be717acc546cea661ac6884930139077fe4ed";
      };
    };
    source = sources."${channel}";
  
negative.code:     /**/"--disable-omx-rpi"
      /**/"--disable-rkmpp"
      "--${boolEn (libva != null)}-vaapi"
      (deprfflag "--disable-vda" null "3.4")  # macOS
      "--${boolEn (libvdpau != null)}-vdpau"
      "--disable-videotoolbox"  # macOS
      # Undocumented
  