Missing typeinfo in wxMac

[Deepak]

I have built wxWindows on MAC (Xcode, GCC 4.0) with RTTI enabled.
However any client that tries to link to this library and tries to
inherit from wxThread gets the following linker error
undefined : type info for wxThread.
(__ZTI8wxThread)

Is there any specific compiler setting to export the type info of a
class?