osmo_io: Add io_uring backend

Change-Id: I5152129eb84b31ccc9e02bc2a5c5bdb046d331bc
diff --git a/src/core/osmo_io_internal.h b/src/core/osmo_io_internal.h
index 0f0465d..5b7ab90 100644
--- a/src/core/osmo_io_internal.h
+++ b/src/core/osmo_io_internal.h
@@ -19,6 +19,10 @@
 extern const struct iofd_backend_ops iofd_poll_ops;
 #define OSMO_IO_BACKEND_DEFAULT "POLL"
 
+#if defined(HAVE_URING)
+extern const struct iofd_backend_ops iofd_uring_ops;
+#endif
+
 struct iofd_backend_ops {
 	int (*register_fd)(struct osmo_io_fd *iofd);
 	int (*unregister_fd)(struct osmo_io_fd *iofd);
@@ -90,9 +94,9 @@
 		} poll;
 		struct {
 			bool read_enabled;
-			bool read_pending;
-			bool write_pending;
 			bool write_enabled;
+			void *read_msghdr;
+			void *write_msghdr;
 			/* TODO: index into array of registered fd's? */
 		} uring;
 	} u;