libqemustub: vmstate register/unregister stubs

Add vmstate stub functions, so that qdev.o can be used without savevm.o
when vmstate support is not necessary (i.e. by *-user).

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>

stubs/Makefile.objs

@@ -6,4 +6,5 @@ stub-obj-y += fdset-remove-fd.o
 stub-obj-y += get-fd.o
 stub-obj-y += set-fd-handler.o
 stub-obj-y += reset.o
+stub-obj-y += vmstate.o
 stub-obj-$(CONFIG_WIN32) += fd-register.o

stubs/vmstate.c

@@ -0,0 +1,17 @@
+#include "qemu-common.h"
+#include "migration/vmstate.h"
+
+int vmstate_register_with_alias_id(DeviceState *dev,
+                                   int instance_id,
+                                   const VMStateDescription *vmsd,
+                                   void *base, int alias_id,
+                                   int required_for_version)
+{
+    return 0;
+}
+
+void vmstate_unregister(DeviceState *dev,
+                        const VMStateDescription *vmsd,
+                        void *opaque)
+{
+}