Changes in release 3.21.25
--------------------------
* Changed `typedef 'string'' to `typedef 'my_string'' for better
portability.
* You can now kill threads that are waiting on a disk-full condition.
* Fixed some problems with UDF functions.
* Added long options to `isamchk'. Try `isamchk --help'.
* Fixed a bug when using 8 bytes long (alpha); `filesort()' didn't
work. Affects `DISTINCT', `ORDER BY' and `GROUP BY' on 64-bit
processors.