mariadb: fast-mutex, brewed-openssl, maxkey 4000

- Replace mutexes with spinlocks (experimental)
- Build with Homebrew OpenSSL instead of bundled [yassl](http://www.yassl.com/yaSSL/Home.html)
- Change max key length from 1000 to 4000 [[diff]](https://gist.githubusercontent.com/anonymous/e5b2c223590075d17043/raw/mariadb-maxkey.diff)