[gf] Create gf services.

* src/gf/gfdrivr.c: Define gf services descriptor
table and `gf_driver_requestor' function.

src/gf/gfdrivr.c

@@ -21,6 +21,8 @@
 #include FT_INTERNAL_STREAM_H
 #include FT_INTERNAL_OBJECTS_H
 #include FT_TRUETYPE_IDS_H
+
+#include FT_SERVICE_GF_H
 #include FT_SERVICE_FONT_FORMAT_H
 
 #include "gf.h"
@@ -425,6 +427,28 @@
     return error;
   }
 
+ /*
+  *
+  * SERVICES LIST
+  *
+  */
+
+  static const FT_ServiceDescRec  gf_services[] =
+  {
+    { FT_SERVICE_ID_GF,          NULL },
+    { FT_SERVICE_ID_FONT_FORMAT, FT_FONT_FORMAT_GF },
+    { NULL, NULL }
+  };
+
+  FT_CALLBACK_DEF( FT_Module_Interface )
+  gf_driver_requester( FT_Module    module,
+                        const char*  name )
+  {
+    FT_UNUSED( module );
+
+    return ft_service_list_lookup( gf_services, name );
+  }
+
 
    FT_CALLBACK_TABLE_DEF
   const FT_Driver_ClassRec  gf_driver_class =
@@ -442,7 +466,7 @@
 
       NULL,                     /* FT_Module_Constructor  module_init   */
       NULL,                     /* FT_Module_Destructor   module_done   */
-      NULL      								/* FT_Module_Requester    get_interface */
+      gf_driver_requester     	/* FT_Module_Requester    get_interface */
     },
 
     sizeof ( GF_FaceRec ),