BEFORE: First packet sent by client-side plugin (generated by Windows
function InitializeSecurityContext()) could be longer than 255 bytes 
violating the limitation imposed by authentication protocol.

AFTER: Handshake protocol is  changed so that if first client's reply is 
longer than 254 bytes then  it is be sent in 2 parts. However, for replies
shorter than 255 bytes nothing changes.

ADDITIONAL CHANGES: 
- The generic packet processing loop  (Handshake::packet_processing_loop) 
has been refactored. Communication with the peer has been abstracted
into virtual methods read/write_packet() which are implemented in client 
and server and transparently do the required splitting and gluing of packets.
- Make it possible to optionally use dbug library in the plugin.
- Add code for testing splitting of long first client reply.

into the server repository

This patch adds client windows authentication plugin code to the client 
library libmysql (only on Windows platform). The plugin is compiled into 
the library and added to the list of built-in plugins. This way clients 
should be able to connect to a server which uses windows authentication 
plugin even as an SQL user which uses such authentication.

Note: this makes the client library to depend on Secur32 Windows system
library. When building clients, they must be linked against Secur32. 
Command mysql_config --libs correctly lists Secur32 as a required 
dependency.

Removed STDCALL from the function definition.

Enabled the ABI check to run on MacOSX.

Partitions can have different ref_length (position data length).
Removed DBUG_ASSERT which crashed debug builds when using
MAX_ROWS on some partitions.

               FAILS WITH LIBEDIT

Fixed by checking the return value of the write()
function calls and handling the open files and fd
appropriately.

 - fix the fix to properly detect when engine is NDB and
   also don't drop the table t9 if it hasn't been created

Fix: it only worked if some worker had valgrind report from its last test
Flag has to be set both places where report is printed

calc_daynr() function returns negative result
if malformed date with zero year and month is used.
Attempt to calculate week day on negative value
leads to crash. The fix is return NULL for
'W', 'a', 'w' specifiers if zero year and month is used.
Additional fix for calc_daynr():
--added assertion that result can not be negative
--return 0 if zero year and month is used

Before sorting HAVING condition is split into two parts,
first part is a table related condition and the rest of is
HAVING part. Extraction of HAVING part does not take into account
the fact that some of conditions might be non-const but
have 'used_tables' == 0 (independent subqueries)
and because of that these conditions are cut off by
make_cond_for_table() function.
The fix is to use (table_map) 0 instead of used_tables in
third argument for make_cond_for_table() function.
It allows to extract elements which belong to sorted
table and in addition elements which are independend
subqueries.