qom: introduce object_register_sugar_prop

Similar to the existing "-rtc driftfix" option, we will convert some
legacy "-machine" command line options to global properties on accelerators.
Because accelerators are not devices, we cannot use qdev_prop_register_global.
Instead, provide a slot in the generic object_compat_props arrays for
command line syntactic sugar.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/qom/object.c b/qom/object.c
index d51b57f..e7b72f7 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -414,10 +414,29 @@
  * Global property defaults
  * Slot 0: accelerator's global property defaults
  * Slot 1: machine's global property defaults
+ * Slot 2: global properties from legacy command line option
  * Each is a GPtrArray of of GlobalProperty.
  * Applied in order, later entries override earlier ones.
  */
-static GPtrArray *object_compat_props[2];
+static GPtrArray *object_compat_props[3];
+
+/*
+ * Retrieve @GPtrArray for global property defined with options
+ * other than "-global".  These are generally used for syntactic
+ * sugar and legacy command line options.
+ */
+void object_register_sugar_prop(const char *driver, const char *prop, const char *value)
+{
+    GlobalProperty *g;
+    if (!object_compat_props[2]) {
+        object_compat_props[2] = g_ptr_array_new();
+    }
+    g = g_new0(GlobalProperty, 1);
+    g->driver = g_strdup(driver);
+    g->property = g_strdup(prop);
+    g->value = g_strdup(value);
+    g_ptr_array_add(object_compat_props[2], g);
+}
 
 /*
  * Set machine's global property defaults to @compat_props.
@@ -445,7 +464,7 @@
 
     for (i = 0; i < ARRAY_SIZE(object_compat_props); i++) {
         object_apply_global_props(obj, object_compat_props[i],
-                                  &error_abort);
+                                  i == 2 ? &error_fatal : &error_abort);
     }
 }