We're currently using a fork of GCC because its [JS version](https://github.com/google/closure-compiler-js) is not updated yet to the GCC version that includes https://github.com/google/closure-compiler/pull/2707. See https://github.com/google/closure-compiler-js/pull/83#issuecomment-344099311. When there is a new release of the JS version that includes that PR, we should remove [this fork](https://github.com/facebook/react/blob/7e692fb496e764844680c681a38e42f99e1f218d/yarn.lock#L2169).
We're currently using a fork of GCC because its JS version is not updated yet to the GCC version that includes google/closure-compiler#2707. See google/closure-compiler-js#83 (comment).
When there is a new release of the JS version that includes that PR, we should remove this fork.