Figure out how to be compatible with MariaDB

[tnozicka]

MariaDB has striped down some symbols that we use to fix design flaws in C API. Particularly THR_LOCK_threads, THR_KEY_mysys, THR_COND_threads, THR_thread_count.

Temporary fix migth be some macro to disable these fixes resulting in small memory leaks in C API TSS (thread specific storage).