qapi: Introduce a first class 'any' type

It's first class, because unlike '**', it actually works, i.e. doesn't
require 'gen': false.

'**' will go away next.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c
index d7f92c5..737deab 100644
--- a/qapi/qapi-dealloc-visitor.c
+++ b/qapi/qapi-dealloc-visitor.c
@@ -151,6 +151,14 @@
 {
 }
 
+static void qapi_dealloc_type_anything(Visitor *v, QObject **obj,
+                                       const char *name, Error **errp)
+{
+    if (obj) {
+        qobject_decref(*obj);
+    }
+}
+
 static void qapi_dealloc_type_size(Visitor *v, uint64_t *obj, const char *name,
                                    Error **errp)
 {
@@ -216,6 +224,7 @@
     v->visitor.type_bool = qapi_dealloc_type_bool;
     v->visitor.type_str = qapi_dealloc_type_str;
     v->visitor.type_number = qapi_dealloc_type_number;
+    v->visitor.type_any = qapi_dealloc_type_anything;
     v->visitor.type_size = qapi_dealloc_type_size;
     v->visitor.start_union = qapi_dealloc_start_union;