package aliased;

BEGIN {
    eval { require Scalar::Util };
    if(  defined &Scalar::Util::refaddr  ) {
        *refaddr= \&Scalar::Util::refaddr;
    } else {
        eval { require overload };
        if(  defined &overload::Overloaded  ) {
            *refaddr= sub {
                if(  overload::Overloaded( $_[0] )  ) {
                    require Carp;
                    Carp::confess( "Upgrade Scalar::Util ..." );
                }
                return 0+$_[0];
            };
        } else {
            *refaddr= sub { 0+$_[0] };
        }
    }
}

...