build-sys: re-add old symbols for abi compat

For two releases those exported with version 183 by mistake, and then
they were fixed to have version 215 (015419c0df libudev: fix symbol
version for udev_queue_flush() and udev_queue_get_fd()). But that
breaks ABI compatibility for binaries compiled with udev from before
that commit. There most likely very few such binaries, if any, but as
a matter of principle we should export the old symbols too, in order
to keep full compatibility.

src/libudev/libudev-queue.c

@@ -268,3 +268,6 @@ _public_ int udev_queue_flush(struct udev_queue *udev_queue) {
 
         return flush_fd(udev_queue->fd);
 }
+
+__asm__(".symver udev_queue_flush,udev_queue_flush@LIBUDEV_183");
+__asm__(".symver udev_queue_get_fd,udev_queue_get_fd@LIBUDEV_183");