connections
The problem is that tables can enter open table cache for a thread without 
being properly cleaned up. This can happen if make_join_statistics() fails 
to read a const table because of e.g. a deadlock. It does set a member of 
TABLE structure to a value it allocates, but doesn't clean-up this setting 
on error nor does it set the rest of the members in JOIN to allow for 
automatic cleanup.
As a result when such an error occurs and the next statement depends re-uses 
the table from the open tables cache it will get it with this 
TABLE::reginfo.join_tab pointing to a memory area that's freed.
Fixed by making sure make_join_statistics() cleans up TABLE::reginfo.join_tab 
on error.

In case of ROW item each compared pair does not
check if argumet collations can be aggregated and
thus appropiriate item conversion does not happen.
The fix is to add the check and convertion for ROW
pairs.

configure.in

Replacing AC_CHECK_FUNC+AC_CHECK_LIB combination with
AC_SEARCH_LIBS.

returns short string value. 
 
Multibyte character sets were not taken into account when 
calculating max_length in Item_param::convert_str_value(). As a 
result, string parameters of a prepared statement could be 
truncated later when calculating string length in characters by 
dividing length in bytes by the charset's mbmaxlen value (e.g. in 
Field_varstring::store()). 
 
Fixed by taking charset's mbmaxlen into account when calculating 
max_length in Item_param::convert_str_value().

      
Removed the misleading "NOTE:" from the \h command. 

replace wild_case_compare with my_wildcmp which is multibyte safe function

Substitute all references of MySQL version "5.2" to "6.0" in
deprecation warning messages.Deprecated constructs are being
removed in the 6.0 tree.

stack reservation too small

Problem: some tests fail on HP-UX due to insufficient stack reservation.

Fix: increase stack reservation.