fix XorShiftRng cannot clone
@@ -15,6 +15,7 @@ use crate::vm::{
#[derive(Clone, Debug, Userdata, Trace, VmType)]
#[gluon(vm_type = "std.random.XorShiftRng")]
+#[gluon_userdata(clone)]
#[gluon(crate_name = "::vm")]
#[gluon_trace(skip)]
struct XorShiftRng(self::rand_xorshift::XorShiftRng);
