ColumnStore used to include server's mysql.h
but link all tools with libmariadb.so
There's no guarantee that this would work, even with workarounds
it had in dbcon/mysql/sm.cpp
Fix:
* tools (linked with libmariadb.so) *must* include libmariadb's mysql.h
* as a hack prevent service_thd_timezone.h from being loaded into tools,
as it conflicts with libmariadb's mysql.h
* server plugin *must* include server's mysql.h
* also don't link every tool with libmariadb.so, link the helper library
(liblibmysqlclient.so) that actually needs it, tools use this
helper library, not libmariadb.so directly