Add universal way to shutdown sockets on Wine side

src/wine-host/bridges/common.h

@@ -102,6 +102,14 @@ class HostBridge {
     const boost::filesystem::path plugin_path;
 
    protected:
+    /**
+     * Used as part of the watchdog that shuts down a plugin when the remote
+     * native host process dies. This is used to prevent plugins from hanging
+     * indefinitely on a `recv()`. This function should just call
+     * `sockets.close()`.
+     */
+    virtual void close_sockets() = 0;
+
     /**
      * The IO context used for event handling so that all events and window
      * message handling can be performed from a single thread, even when hosting