support patchfile on all platforms
support patchfile on all platforms

Summary: Adding patching support for all platforms using `git apply`

Reviewed By: xavierd

Differential Revision: D36939728

fbshipit-source-id: ccf6e4ccd30257c6928ba804a76882d4d2f71700

facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst,facebookincubator/mvfst