Summary:
Original commit changeset: c6f013565680

Redo D22417488 (https://github.com/facebook/folly/commit/43d80f110b181dd7f72f0f935322a58f9cbb5147), with D22577887 fixing open source CI builds

Reviewed By: wez

Differential Revision: D22577884

fbshipit-source-id: 0c94483e05715493859d29bc2b58f0847a95826b