Fix bug MDEV-4895 Valgrind warnings (Conditional jump or move depends on uninitialised value) in Field_datetime::get_date on GREATEST(..) IS NULL

Analysis:
The cause of the valgrind warning was an attempt to evaluate a Field that was not yet read.
The reason was that on one hand Item_func_isnotnull was marked as constant by
Item_func_isnotnull::update_used_tables, and this allowed eval_const_cond() to be called.
On the other hand Item_func_isnotnull::val_int() evaluated its argument as if it was not
constant.

Solution:
The fix make sure that Item_func_isnotnull::val_int() doesn't evaluate its argument when
it is constant and cannot be NULL, because the result is known in this case. 

had been discovered when merging the patch from 5.3 into 5.5.

After single row substitutions there might appear new equalities.
They should be properly propagated to all AND/OR levels the WHERE
condition. It's done now with an additional call of remove_eq_conds(). 

This patch almost totally revised the patch for bug mdev-4177.
The latter had too many defects. In particular, it did not
propagate multiple equalities formed when merging a degenerate
disjunct into underlying AND formula.

This a an old legacy performance bug.
When a very selective range scan existed for the second table in a join,
and, at the same time, there was another range condition depending on the
fields of the first table, the optimizer chose a plan with
'Range checked for each record'. This plan was extremely inefficient in
comparison with the regular selective range scan.
As a matter of fact the range scan chosen for each record was the same as
that selective range scan. 

Changed the test case for bug 24776 to preserve the old output for explain.
 

MDEV-4812 Valgrind warnings (Invalid write) in dynamic_column_update_many on COLUMN_ADD

Fixed problem of working on wrong data (do not allow offset to out of string length).

Fixing a typo:  bit AND (&) was erroneously used instead of logical AND (&&) 

MDEV-4823: Server crashes in Item_func_not::fix_fields on creating a table with a virtual column using NOT

fix_field() call protocol was brocken (zero pointer passed as link to item which is possible only if you are sure that there can not be Items which transforms).

   not_enough_points() introduced to check if the spatial object is incorrect.

MDEV-4409 - Fix deadlock in MySQL key cache code, that can happen if there is a key cache resize running in parallel with an update.

If there is a key cache resize,a  thread writing to key cache, will pause waiting  until resize finishes. However this thread is won't be woken, because resize does not  signaling waiters anymore. This is a regression introduced in WL#86(segmented MyISAM key cache)
The fix is to unconditionally release  threads waiting on resize_queue when resize  finishes, as in pre-WL#86 code.

modified:
  mysql-test/suite/plugins/r/fulltext_plugin.result
  mysql-test/suite/plugins/t/fulltext_plugin.test
  plugin/fulltext/plugin_example.c
  sql/sql_show.cc
pending merges:
  Alexander Barkov 2013-07-09 [merge] Merge from 5.1
    Sergei Golubchik 2013-07-06 Bug #69682 - mysqld crashes after uninst...
    Sergei Golubchik 2013-05-24 MDEV-4575 MySQL client doesn't strip off...

modified:
  mysql-test/suite/plugins/r/fulltext_plugin.result
  mysql-test/suite/plugins/t/fulltext_plugin.test
  plugin/fulltext/plugin_example.c
  sql/sql_show.cc
pending merges:
  Sergei Golubchik 2013-07-06 Bug #69682 - mysqld crashes after uninstall ...
    Sergei Golubchik 2013-05-24 MDEV-4575 MySQL client doesn't strip off...

MDEV-4643 MariaDB crashes consistently when trying a SELECT on VIEW with a UNION and an additional JOIN in SELECT

open derived temp tables *before* trying QUICK_SELECT for them,
handler::multi_range_read_info() needs an open table.

don't ignore the return value fix_fields()

MDEV-4257 Assertion `!table || (!table->read_set || bitmap_is_set(table->read_set, field_index))' fails on FROM subquery with fulltext search, derived_merge=on

remove emtpty Item_func_match::update_used_tables() method

Cleanup: remove TIME_FUZZY_DATE.

Introduce TIME_FUZZY_DATES which means "very fuzzy, the resulting
value is only used for comparison. It can be invalid date, fine, as long as it can be
compared".

Updated many tests results (they're better now).

modified:
  sql/time.cc

Item_func_min_max::get_date() did not check the
returned value against the fuzzy_date flags, so
it could return a bad value to the caller that
expects a good date (e.h. CONVERT_TZ).


modified:
  mysql-test/r/type_date.result
  mysql-test/r/type_datetime.result
  mysql-test/r/type_time.result
  mysql-test/t/type_date.test
  mysql-test/t/type_datetime.test
  mysql-test/t/type_time.test
  sql/item_func.cc
  sql/item_timefunc.cc
  sql/mysql_priv.h
  sql/time.cc

modified:
  mysql-test/r/func_time.result
  mysql-test/t/func_time.test
  sql/item_timefunc.cc
  sql/mysql_priv.h

modified:
  mysql-test/r/ps_2myisam.result
  mysql-test/r/ps_3innodb.result
  mysql-test/r/ps_4heap.result
  mysql-test/r/ps_5merge.result
  mysql-test/r/type_datetime_hires.result
  mysql-test/suite/maria/r/ps_maria.result
  mysql-test/t/type_datetime_hires.test
  sql/item_timefunc.h

mysql_derived_merge_for_insert() should not be called for views or derived tables which are not put (directly or via other views) in main SELECT_LEX "join list".

extend 5.1 client library to read 4 byte capabilities from the first handshake packet.
two higher bytes are always zeros for 5.1 servers.

MDEV-4280: Assertion `empty_size == empty_size_on_page' failure in ma_blockrec.c or ER_NOT_KEYFILE on query with DISTINCT and GROUP BY
This could happen when using Aria for internal temporary files (default case) and using DISTINCT.
_ma_scan_restore_block_record() didn't work correctly if there was rows inserted, updated or deleted on the handler
between calls to _ma_scan_remember_block_record() and _ma_scan_restore_block_record().
The effect was that some DISTINCT queries that used remove_dup_with_compare() could fail.

.bzrignore:
  Ignore sql_yacc.hh
mysql-test/suite/maria/r/distinct.result:
  Test case for MDEV-4280
mysql-test/suite/maria/t/distinct.test:
  Test case for MDEV-4280
mysql-test/t/mysql.test:
  Fixed test suite (we could get error -1 in some cases)
sql/sql_select.cc:
  Break loop if restart_rnd_next() gives an error
storage/maria/ha_maria.cc:
  scan_restore_pos() can return disk fault error.
storage/maria/ma_blockrec.c:
  _ma_scan_remember_block_record() did incorrectly update scan.dir instead of scan_save.dir .
  _ma_scan_restore_block_record() didn't work correctly if there was rows inserted,updated or deleted on the handler
  between calls to _ma_scan_remember_block_record() and _ma_scan_restore_block_record().
  Fixed by adding counters for row changes and reading the current scan page if changes had been made.
storage/maria/ma_blockrec.h:
  scan_restore_pos() can return disk fault error.
storage/maria/ma_delete.c:
  Increment row_changes
storage/maria/ma_scan.c:
  scan_restore_pos() can return disk fault error.
storage/maria/ma_update.c:
  Increment row_changes
storage/maria/ma_write.c:
  Increment row_changes
storage/maria/maria_def.h:
  scan_restore_pos() can return disk fault error.

avoid divison by zero

Fix agregate function resolution in derived tables (no name resolution over a derived table border)