Summary: - cmake: use the builtin FindBzip2.cmake from CMake - cmake: require CMake v3.5.1 - cmake: add imported target for 3rd party libraries - cmake: extract ReadVersion.cmake out and refactor it Pull Request resolved: https://github.com/facebook/rocksdb/pull/5662 Differential Revision: D16660974 Pulled By: maysamyabandeh fbshipit-source-id: 681594910e74253251fe14ad0befc41a4d0f4fd4