[Draft] unix_socket authentication does not work on some machines

MariaDB [test]> select @@version;

+----------------------+

| @@version            |

+----------------------+

| 5.5.54-MariaDB-debug |

+----------------------+

1 row in set (0.00 sec)

MariaDB [test]> install soname 'auth_socket';

Query OK, 0 rows affected (0.05 sec)

MariaDB [test]> create user elenst identified via 'unix_socket';

Query OK, 0 rows affected (0.00 sec)

MariaDB [test]> select @@socket;

+-----------------------------------+

| @@socket                          |

+-----------------------------------+

| /data/bld/5.5/data/tmp/mysql.sock |

+-----------------------------------+

1 row in set (0.00 sec)

MariaDB [test]> exit

Bye

elenst@jessie:/data/bld/5.5$ whoami

elenst

elenst@jessie:/data/bld/5.5$ bin/mysql --socket=/data/bld/5.5/data/tmp/mysql.sock -uelenst

ERROR 1698 (28000): Access denied for user 'elenst'@'localhost'

elenst@jessie:/data/bld/5.5$ bin/mysql --socket=/data/bld/5.5/data/tmp/mysql.sock -uroot -p

Enter password: 

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Server version: 5.5.54-MariaDB-debug Source distribution

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