MySQL bug http://bugs.mysql.com/bug.php?id=61713 was fixed in 5.5
  
Fix is to remove check for multiple entries returned by getaddrinfo(), and use the first entry that works  - i.e socket can be created.  

Unlike Oracle/MySQL's fix ,this one  is kept minimal : 
-  we do not prioritize IPv4 over IPv6,  orr other way around,  and just rely on operating system to sort getaddrinfo() entries in sensible order. There is RFC that defines  what is sensible order for getaddrinfo entries ( RFC 3484), and OS specific tweaks are also possible , like /etc/gai.conf o Linux.
-  also,  we do not force "0.0.0.0" address if bind-address is not given -  this would be a change in behavior of 5.5 at least on Windows, where passing NULL as  to getaddrinfo()  gives back IPv6-wildcard.

fixes for gcc 4.8 - compilation warnings and -fsanitize=address

fixes for gcc 4.8 -fsanitize=address

fulltext search was initialized for all MATCH ... AGAINST items
at the end of the JOIN::optimize(). But since 5.3 derived tables
are initialized lazily on first use, very late in the sub_select().

Skip Item_func_match::init_search initialization if the corresponding
table isn't open yet; repeat fulltext initialization for all
not-yet-initialized MATCH ... AGAINST items after creating derived tables.

currently get_mm_tree skipped the evaluation of this constant
and icorrectly proceeded. The correct behavior is to return a
NULL subtree, according to the IF branch being fixed - when it
evaluates the constant it returns a value, and doesn't continue
further.

(debug_sync value can have single quotes)

update 5.1 to replicate from 10.0 and
to show the server version (as of 10.0) correctly

sql-common/client.c:
  mdev:4088
sql/slave.cc:
  use the version number, not just the first character of the version string
  (we want 10 > 4 not "10" < "4").

init join->top_join_tab_count to be in sync with join->join_tab=stat,
otherwise a query can be killed in-between and join_tab's won't be deleted
(JOIN::cleanup won't call JOIN_TAB::cleanup)

- Let index_merge allocate table handlers on quick select's MEM_ROOT,
  not on statement's MEM_ROOT. 
  This is crucial for big "range checked for each record" queries, where 
  index_merge can be created and deleted many times during query exection. 
  We should not make O(#rows) allocations on statement's MEM_ROOT.

- When converting a subquery to a semi-join, propagate OPTION_SCHEMA_TABLE.

  
Analysis:
The reason for the inefficent plan was that Item_subselect::is_expensive()
didn't detect the special case when a subquery was optimized, but had no
join plan because it either has no table, or its tables have been optimized
away, or the optimizer detected that the result set is empty.
  
Solution:
Identify the special cases above in the Item_subselect::is_expensive(),
and consider such degenerate subqueries inexpensive.

This bug was introduced by the patch for WL#3220.
If the memory allocated for the tree to store unique elements
to be counted is not big enough to include all of them then
an external file is used to store the elements.
The unique elements are guaranteed not to be nulls. So, when 
reading them from the file we don't have to care about the null
flags of the read values. However, we should remove the flag 
at the very beginning of the process. If we don't do it and
if the last value written into the record buffer for the field
whose distinct values needs to be counted happens to be null,
then all values read from the file  are considered to be nulls
and are not counted in.
The fix does not remove a possible null flag for the read values.
Rather it just counts the values in the same way it was done
before WL #3220.

Extend plugin auth api to support up to 512 bytes in the user names.
Use the API versioning to support old auth plugins too!

          The get_mbr() method shouldn't return the error, rather an invalid MBR
          in this case.

Fixed printing column_get finction.

In some cases, when using views the optimizer incorrectly determined
possible join orders for queries with nested outer and inner joins.
This could lead to invalid execution plans for such queries.

        The Geometry::get_mbr() function can return an error on
        a bad data. We have to check for that and act respectively.

- Set MI_INFO::external_ref for MyISAM tables that are parts of myisamMRG table.

./mtr --suite=main,plugins
will work on all branches.

MDEV-4293 Valgrind warnings (Conditional jump or move depends on uninitialised value) in remove_eq_conds on time functions with NULL argument

val_int() is expected to return 0 for NULL's