yt-dlp: add checkPhase to detect unsupported library

      ''--prefix PATH : "${lib.makeBinPath packagesToBinPath}"''

    ];

  # Requires network

  doCheck = false;

  postInstall = ''

  checkPhase = ''

    # Check for "unsupported" string in yt-dlp -v output.

    output=$($out/bin/yt-dlp -v 2>&1 || true)

    if echo $output | grep -q "unsupported"; then

      echo "ERROR: Found \"unsupported\" string in yt-dlp -v output."

      exit 1

    fi

  ''

  + ''

  '';

  postInstall = ''

    installManPage yt-dlp.1

    installShellCompletion \