commit da38366960d4d25b3dfbf47220ab8129392cc130
Author: Mark Glines <mark@glines.org>
Date:   Wed Apr 22 09:40:10 2009 -0700

    [netbsd] netbsd-alpha fails to compile due to passing NULL in place of a va_list argument.
    va_list is not always a pointer type, this is not a requirement of C89.
    
    This patch implements allison++'s suggestion to more cleanly build a null CallSignature object.

diff --git a/src/pmc/class.pmc b/src/pmc/class.pmc
index f8890d9..e520486 100644
--- a/src/pmc/class.pmc
+++ b/src/pmc/class.pmc
@@ -335,7 +335,11 @@ initialize_parents(PARROT_INTERP, PMC *object, PMC *all_parents)
         meth = Parrot_oo_find_vtable_override_for_class(interp, parent, name);
 
         if (!PMC_IS_NULL(meth)) {
-            PMC *sig_obj = Parrot_pcc_build_sig_object_from_varargs(interp, object, "->", NULL);
+            /* build an empty signature; it has an invocant but no args/retvals */
+            PMC *sig_obj = pmc_new(interp, enum_class_CallSignature);
+            VTABLE_set_string_native(interp, sig_obj, CONST_STRING(interp, "Pi->"));
+            /* add the invocant */
+            VTABLE_unshift_pmc(interp, sig_obj, object);
             Parrot_pcc_invoke_from_sig_object(interp, meth, sig_obj);
             gc_unregister_pmc(interp, sig_obj);
         }