[vala/0.40] gobject-2.0: Fix bootstrap with valac < 0.26

[Rico Tzschichholz <ricotz src gnome org>]

commit 6bbf1c6189993561f365078201fbdd5b53f1e735
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Wed Mar 21 15:27:53 2018 +0100

    gobject-2.0: Fix bootstrap with valac < 0.26

 vapi/gobject-2.0.vapi |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/vapi/gobject-2.0.vapi b/vapi/gobject-2.0.vapi
index 153d0fd..665be78 100644
--- a/vapi/gobject-2.0.vapi
+++ b/vapi/gobject-2.0.vapi
@@ -179,7 +179,11 @@ namespace GLib {
                public static unowned GLib.ParamSpec? interface_find_property (GLib.TypeInterface g_iface, 
string property_name);
                public static void interface_install_property (GLib.TypeInterface g_iface, GLib.ParamSpec 
pspec);
                [CCode (array_length_pos = 1.1, array_length_type = "guint")]
+#if VALA_0_26
                public static (unowned GLib.ParamSpec)[] interface_list_properties (GLib.TypeInterface 
g_iface);
+#else
+               public static unowned GLib.ParamSpec[] interface_list_properties (GLib.TypeInterface g_iface);
+#endif
                public bool is_floating ();
                public static GLib.Object @new (GLib.Type type, ...);
                public static GLib.Object new_valist (GLib.Type type, string? firstprop, va_list var_args);