With Rust 1.26 parking_lot_core fails to compile

[nobleach]

While attempting to fire up the very core demo project from the actix.rs website, I'm getting a compile error:

error[E0432]: unresolved import `std::sync::atomic::spin_loop_hint`
  --> /Users/jimwharton/.cargo/registry/src/github.com-1ecc6299db9ec823/parking_lot_core-0.2.14/src/spinwait.rs:14:5
   |
14 | use std::sync::atomic::spin_loop_hint;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no `spin_loop_hint` in `sync::atomic`

   Compiling tempdir v0.3.7
error: aborting due to previous error

error: Could not compile `parking_lot_core`.
warning: build failed, waiting for other jobs to finish...
error: build failed

I've done a bit of looking around, but I'm not seeing any real leads. I'm using stable. The only dep in my Cargo.toml is actix-web = "0.6"

[nobleach]

Apparently, I still had a brew install of rust sitting in my path. rustc --version showed v1.21. My apologies.