Linux: Fix recent entries with quote in filename

According to RFC 2396, the single quote character (') is allowed in uri
strings and is not escaped by gtk, so the action string constructed for
the recent files menu must be quoted with " instead of '.

This fixes issue #437

desmume/src/frontend/posix/gtk/main.cpp

@@ -3383,7 +3383,7 @@ common_gtk_main(GApplication *app, gpointer user_data)
         const char *name = gtk_recent_info_get_display_name(info);
         // TODO: Is that enough?  Maybe allocate instead?
         char action[1024];
-        sprintf(action, "app.recent('%s')", uri);
+        sprintf(action, "app.recent(\"%s\")", uri);
         g_menu_append(G_MENU(user_data), name, action);
 
         gtk_recent_info_unref(info);