stubs: fully replace qemu-tool.c and qemu-user.c

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/stubs/migr-blocker.c b/stubs/migr-blocker.c
new file mode 100644
index 0000000..300df6e
--- /dev/null
+++ b/stubs/migr-blocker.c
@@ -0,0 +1,10 @@
+#include "qemu-common.h"
+#include "migration/migration.h"
+
+void migrate_add_blocker(Error *reason)
+{
+}
+
+void migrate_del_blocker(Error *reason)
+{
+}