Bug #17123 fulltext plugin may not pass on allocated memory

Description:
When creating a fulltext plugin that preprocesses data in a malloced buffer
the words to be put into the index are mangled as with_alloc is not set
for the custom parser (and is not settable from outside ./storage/myisam/ft_parser.c
either)

How to repeat:
static int dummy_parse(MYSQL_FTPARSER_PARAM *param)
{
  char *doc = malloc(param->length);
  int result;

  memcpy(doc, param->doc, param->length);
  result = param->mysql_parse(param->mysql_ftparam, doc, param->length);
  free(doc);   // works fine only when *not* freeing memory after call here
  return result;
}

Suggested fix:
either always set with_alloc to true when calling fulltext plugins 
or provide the needed structure definitions in plugin.h to make
this settable from within the plugins parse functuon using param->mysql_ftparam

Not useless - an easy workaround is to store the pointer somewhere in the ftparser_state and do not free the memory until plugin->deinit() call.

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/7024

Two changes worth documenting:

1. MYSQL_FTPARSER_PARAM structure got new field: flags.
   The only possible value for now is MYSQL_FTFLAGS_NEED_COPY.
   It means that mysql_add_word() needs to save a copy of the word, it cannot
   use a pointer to it, because the word is in the buffer that will be overwritten.

  The flag may be set or reset on any level - by MySQL before calling the parser
  plugin, by the parser plugin itself, or by mysql_parse() function.

2. mysql_parse() and mysql_add_word() now take MYSQL_FTPARSER_PARAM as
   the first argument, not MYSQL_FTPARSER_PARAM::mysql_ftparam as before.

As these changes are not backward compatible, the API version was changed.

fixed in 5.1.12

Noted in 5.1.12 changelog, and I've updated the
instructions on parser plugin writing to match.

I tried this code in mysql 5.1.12

ptext = (char*)malloc(5);
strncpy(ptext, "king", 4);
param->mysql_parse(param, ptext, 4);

in fulltext parser and it still doesn't work. :(