replay: add BH oneshot event for block layer

Replay is capable of recording normal BH events, but sometimes
there are single use callbacks scheduled with aio_bh_schedule_oneshot
function. This patch enables recording and replaying such callbacks.
Block layer uses these events for calling the completion function.
Replaying these calls makes the execution deterministic.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
Acked-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/stubs/replay-user.c b/stubs/replay-user.c
new file mode 100644
index 0000000..2ad9e27
--- /dev/null
+++ b/stubs/replay-user.c
@@ -0,0 +1,9 @@
+#include "qemu/osdep.h"
+#include "sysemu/replay.h"
+#include "sysemu/sysemu.h"
+
+void replay_bh_schedule_oneshot_event(AioContext *ctx,
+    QEMUBHFunc *cb, void *opaque)
+{
+    aio_bh_schedule_oneshot(ctx, cb, opaque);
+}