ui/gtk: Ignore 2- and 3-button press events

GTK already produces corresponding GDK_BUTTON_PRESS events
alongside 2BUTTON and 3BUTTON_PRESS events. The 2BUTTON and
3BUTTON_PRESS events were incorrectly being interpreted and
passed to guests as button release events.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/558
Signed-off-by: K. Lange <klange@toaruos.org>
Message-Id: <20220305104521.3583703-1-klange@toaruos.org>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

ui/gtk.c

@@ -972,6 +972,10 @@ static gboolean gd_button_event(GtkWidget *widget, GdkEventButton *button,
         return TRUE;
     }
 
+    if (button->type == GDK_2BUTTON_PRESS || button->type == GDK_3BUTTON_PRESS) {
+        return TRUE;
+    }
+
     qemu_input_queue_btn(vc->gfx.dcl.con, btn,
                          button->type == GDK_BUTTON_PRESS);
     qemu_input_event_sync();