Drop finalizer on newtype structs does not work

[brson]

This will leak the ptr. Valgrind will complain.

use core::libc::{c_void, malloc, free};

struct SmartPtr(*c_void);

impl Drop for SmartPtr {
    fn finalize(&self) {
        unsafe {
            error!("end ptr: %x", **self as uint);
            free(**self);
        }
    }
}

fn main() {
    unsafe {
        let junk = malloc(4);
        error!("start ptr: %x", junk as uint);
        let _junkbox = SmartPtr(junk);
    }
}

[brson]

Nominating feature complete.

[luqmana]

This seems to be because the drop flag isn't set for newtype structs meaning the branch which calls the actual destructor in trans::glue doesn't get executed. The function that sets the drop flag appropriately is middle::trans::adt::trans_start_init but it doesn't seem to be called.

[graydon]

accepted for production ready

[luqmana]

Fixed per #6125.