[vala/0.40] girwriter: Properly resolve GLib.TypeInterface instead of hardcoding it

[Rico Tzschichholz <ricotz src gnome org>]

commit 42ccb4cbe3c796d87a9a7372c549acbee6cc70c2
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Sat Apr 27 11:17:28 2019 +0200

    girwriter: Properly resolve GLib.TypeInterface instead of hardcoding it
    
    This makes sure to pick up the dependency on GObject-2.0.gir

 codegen/valagirwriter.vala | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/codegen/valagirwriter.vala b/codegen/valagirwriter.vala
index f5d8eb8cd..d812de79f 100644
--- a/codegen/valagirwriter.vala
+++ b/codegen/valagirwriter.vala
@@ -111,6 +111,7 @@ public class Vala.GIRWriter : CodeVisitor {
 
        private TypeSymbol gobject_type;
        private TypeSymbol ginitiallyunowned_type;
+       private TypeSymbol gtypeinterface_type;
 
        private struct GIRNamespace {
                public GIRNamespace (string ns, string version) {
@@ -153,6 +154,7 @@ public class Vala.GIRWriter : CodeVisitor {
                var glib_ns = root_symbol.scope.lookup ("GLib");
                gobject_type = (TypeSymbol) glib_ns.scope.lookup ("Object");
                ginitiallyunowned_type = (TypeSymbol) glib_ns.scope.lookup ("InitiallyUnowned");
+               gtypeinterface_type = (TypeSymbol) glib_ns.scope.lookup ("TypeInterface");
 
                write_package (package);
 
@@ -554,7 +556,7 @@ public class Vala.GIRWriter : CodeVisitor {
                buffer.append_printf ("<field name=\"parent_iface\">\n");
                indent++;
                write_indent ();
-               buffer.append_printf ("<type name=\"GObject.TypeInterface\" c:type=\"GTypeInterface\"/>\n");
+               buffer.append_printf ("<type name=\"%s\" c:type=\"%s\"/>\n", gi_type_name 
(gtypeinterface_type), get_ccode_name (gtypeinterface_type));
                indent--;
                write_indent ();
                buffer.append_printf ("</field>\n");