MDEV-30275: mariadb names rather than mysql names should be used
Fix bug in mariadb-service-convert
If mariadb-service-convert is run and the user variable is unset then
this sets `User=` in `[Service]`, which then tries to run mariadb as
root, which in-turn fails. This only happens when mysqld_safe is missing
which is all the time now. So...
1. Don't set `User=` if there is no user variable.
2. User mariadbd-safe instead.
Also
* galera_recovery to use mariadbd
* mtr - wsrep use mariadb executables
* debian/mariadb-server.mariadb.init use mariadbd-safe
* debian/tests/smoke uses mariadb instead of mysql as client.
Eventually mysql symlinks will go away, as MariaDB and MySQL keep
diverging and we do not want to make it impossible to install
MariaDB and MySQL side-by-side when users want it.
It also useful if people start using MariaDB tools with MariaDB.
If the exe doesn't begine with "mariadb" or is a symlink,
print a warning to use the resolved name.
In my_readlink, add check on my_thread_var as its used by comp_err
and other build utils that also use my_init.
MDEV-29668 SUPER should not allow actions that have fine-grained dedicated privileges
SUPER privilege used to allow various actions that were alternatively
allowed by one of BINLOG ADMIN, BINLOG MONITOR, BINLOG REPLAY,
CONNECTION ADMIN, FEDERATED ADMIN, REPL MASTER ADMIN, REPL SLAVE ADMIN,
SET USER, SLAVE MONITOR.
Now SUPER no longer does that, one has to grant one of the fine-grained
privileges above to be to perform corresponding actions.
On upgrade from MariaDB versions 10.11 and below all the privileges
above are granted automatically if the user has SUPER.
As a side-effect, such an upgrade will allow SUPER-user to run SHOW
BINLOG EVENTS, SHOW RELAYLOG EVENTS, SHOW SLAVE HOSTS, even if he wasn't
able to do it before the upgrade.