Wrong prototype for _gfortran_is_extension_of

[Thomas Koenig]

Hi FX,

> I’ve done that, but still the front-end does not seem to “find” that function decl later

I've had that situation with gfc_resolve_fe_runtime_error.
The solution isn't pretty, because strictly this is a violation
of the translation phases. However, it works, maybe it works for
you too:

   c->resolved_sym = gfc_get_intrinsic_sub_symbol (name);
   /* We set the backend_decl here because runtime_error is a
      variadic function and we would use the wrong calling
      convention otherwise.  */
   c->resolved_sym->backend_decl = gfor_fndecl_runtime_error;
}

Regards

	Thomas