Summary:
This PR contains the following fixes:

1. Fixing Makefile to support non-default locations of developer tools

2. Fixing compile error using a patch from https://github.com/facebook/rocksdb/pull/4007
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4687

Differential Revision: D13287263

Pulled By: riversand963

fbshipit-source-id: 4525eb42ba7b6f82af5f9bfb8e52fa4024e27ccc