James Munns: couldn't be too lucky :)
```
error[E0432]: unresolved import `alloc::sync`
   --> /home/zeenix/.cargo/git/checkouts/postcard-61cf7fed750d5b6b/93d4ba2/source/postcard/src/max_size.rs:5:33
    |
5   | use alloc::{boxed::Box, rc::Rc, sync::Arc};
    |                                 ^^^^ could not find `sync` in `alloc`
    |
note: found an item that was configured out
   --> /home/zeenix/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/lib.rs:252:9
    |
252 | pub mod sync;
    |         ^^^^

```