Summary:
When building with MSVC and vcpkg, dependencies come in both debug and release versions. Fix the searching logic to search for both names and handle them appropriately.

Also silence a few warnings under MSVC 2015 Update 3.

Reviewed By: yfeldblum

Differential Revision: D7683367

fbshipit-source-id: 662fcc7170b260f129610ed47b6afedbe20933b7