client packages need my_global.h and/or my_config.h

after MDEV-13370 server includes got installed under /usr/include/mysql/server. But some client packages need them, e.g. mysql-python needs my_config.h.

They shouldn't need them and mysql-python doesn't really use the included file, but some might use them and they need time to be fixed.

Possible solution, install headers, like

#include "server/my_global.h"

#warning Clients should not include this file, it's a server header. Report a bug to project maintainers!