The `threads` module is no longer used.

Build.PL

@@ -80,20 +80,6 @@ my $builder = Module::Build->new(
                                             #'Text::CharWidth' => 0,           # this works as fallback
                                            },
                               },

        (
         $gtk_youtube_viewer
         ? (
            threads_support => {
                                description => "Threads support for gtk-youtube-viewer. (with use_threads => 1)",
                                requires    => {
                                             'threads'       => 0,
                                             'Thread::Queue' => 0,
                                            },
                               },
           )
         : ()
        ),
    },

    add_to_cleanup     => ['WWW-YoutubeViewer-*'],