Re-exports do not work across crates

[brson]

If I add std.rs with these contents

import option = hack::option;

export option;                                                                                                         

mod hack {
    import option = option::t;
    export option;
}

I can't access the std::option type from outside the crate.

[lht]

The problem is view_items (view_item_export here) are not written to crate metadata. I'll try to fix this issue.

[lht]

Closed by commits 9bb290c, bd30063 and 5e3ffb6