[sigc] Universal (fat) version of libsigc++ libraries

[john blair <mailtome200420032002 yahoo com>]

I am trying to build libgigc++- on my mac 10.5.5. I want to build a universal binary so I am passing the following options to configure:

--disable-dependency-tracking \
    CXXFLAGS="-arch i386 -arch x86_64" \
    CFLAGS="-arch i386 -arch x86_64" \
    LDFLAGS="-arch i386 -arch x86_64"

But this results in the following error:
ld warning: in ../sigc++/.libs/libsigc-2.0.dylib, file is not of required architecture
Undefined symbols for architecture x86_64:
  "sigc::trackable::trackable()", referenced from:
      sigc::internal::slot_rep::slot_rep(void* (*)(void*), void* (*)(void*), void* (*)(void*))in test_trackable.o
      my_class::my_class()in test_trackable.o
  "sigc::slot_base::slot_base()", referenced from:
      sigc::slot0<void>::slot0()in test_trackable.o
  "sigc::internal::slot_rep::notify(void*)", referenced from:
      sigc::internal::slot_do_bind::operator()(sigc::trackable const*) constin test_trackable.o
  "sigc::trackable::remove_destroy_notify_callback(void*) const", referenced from:
      sigc::internal::slot_do_unbind::operator()(sigc::trackable const*) constin test_trackable.o
  "sigc::slot_base::slot_base(sigc::internal::slot_rep*)", referenced from:
      sigc::slot0<void>::slot0<sigc::bound_mem_functor0<void, my_class> >(sigc::bound_mem_functor0<void, my_class> const&)in test_trackable.o
  "sigc::trackable::~trackable()", referenced from:
      sigc::internal::slot_rep::~slot_rep()in test_trackable.o
      sigc::internal::slot_rep::~slot_rep()in test_trackable.o
      my_class::~my_class()in test_trackable.o
  "sigc::trackable::add_destroy_notify_callback(void*, void* (*)(void*)) const", referenced from:
      sigc::internal::slot_do_bind::operator()(sigc::trackable const*) constin test_trackable.o
  "sigc::slot_base::operator=(sigc::slot_base const&)", referenced from:
      sigc::slot0<void>::operator=(sigc::slot0<void> const&)in test_trackable.o
  "sigc::slot_base::~slot_base()", referenced from:
      sigc::slot0<void>::~slot0()in test_trackable.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status


Can someone suggest me a way to build a univeral libsigcc++?