Summary:
This apparently gives better compiler error messages.

Pull Request resolved: https://github.com/facebookincubator/fbjni/pull/30

Test Plan: CI

Reviewed By: mhorowitz

Differential Revision: D19396160

Pulled By: dreiss

fbshipit-source-id: 8e86d8c684be81bc74b03bfc58d71f5c21dac095