Packaging for MariaRocks

This is about packaging MyRocks storage engine.

Build steps for the Facebook tree: https://github.com/facebook/mysql-5.6/wiki/Build-Steps

Compiling

• RocksDB requires a recent C++ compiler, more recent than some MariaDB platforms have.
• It's the same with TokuDB, so we can borrow its CMake code for checking compiler version.

Dependencies

RocksDB depends on compression libraries:

• zlip
• snappy
• ....
• zstandard (new addition)

Ubuntu 16.0.4 Xenial LTS has packages for all libraries.
Other versions support a subset.

What to build

MariaRocks must be a loadable module (don't link statically).

Other

Facebook builds RocksDB with Jemalloc (we build Toku with Jemalloc, too)