Set it to 0 by default.
Now only the tests that use persistent statistics tables require
starting the server with --stat-tables set on.

the server crashed when running the query with persistent statistics
enabled.
The field KEY::read_stat.avg_frequency must be initialized to NULL
for the keys of temporary tables.
 

statistical tables instead of the statistics provided by engine.

threads are retrieving events at the same time.

- Workaround linker bug that prevents linking aria test executables
   using -fno-common on OSX
- Skip system readline detection (OSX readline is incompatible one)
- Make Xcode generator work

(see my comments starting from [9 Apr 22:18])

When the function free_tmp_table deletes the handler object for
a temporary table the field TABLE::file for this table should be
set to NULL. Otherwise an assertion failure may occur.

This bug happened because the function find_field_in_view formed
autogenerated names of view columns without a possibility to roll
them back. In some situation it could cause memory misuses reported
by valgrind or even crashes.

        RB-tree index in the MEMORY table fails if it grews over 4G.
        That happened because the old_allocated variable in hp_rb_write_key()
        had the uint type. Changed with the 'size_t' type to be same as the
        'rb_tree.allocated'.

per-file comments:
  storage/heap/hp_write.c
MDEV-80 Memory engine table full at much less than max_heap_table_size with btree index.
        uint->size_t for the 'old_allocated'.

When a view/derived table is converted from merged to materialized the
items from the used_item lists are substituted for items referring to
the fields of the result of the materialization. The problem appeared
with queries employing natural joins. Since the resolution of a natural
join was performed only once the used_item list formed at the second
execution of the query lacked the references to the fields that were
used only in the equality predicates generated for the natural join.

don't cast implicitly an int to a char, when a boolean value is desired.

Fixed additional changed pbxt test cases

The main problem was a bug in CSV where it provided wrong statistics (it claimed the table was empty when it wasn't)
I also fixed wrong freeing of blob's in the CSV handler. (Any call to handler::read_first_row() on a CSV table with blobs would fail)



mysql-test/r/csv.result:
  Added new test case
mysql-test/r/partition_innodb.result:
  Updated test results after fixing bug with impossible partitions and const tables
mysql-test/t/csv.test:
  Added new test case
sql/sql_select.cc:
  Cleaned up code for handling of partitions.
  Fixed also a bug where we didn't threat a table with impossible partitions as a const table.
storage/csv/ha_tina.cc:
  Allocate blobroot onces.

Now install all includes in a flat hierarchy under
$PREFIX/include/mysq/, same as 5.3. User can override with
-DINSTALL_INCLUDEDIR

Fixed compilation problem on windows.


configure.cmake:
  Added test for pthread_attr_getguardsize
include/my_stacktrace.h:
  Define dummy my_init_stacktrace() to allow one to call it without #ifdef HAVE_STACKTRACE
sql/mysqld.cc:
  Move my_setstacksize() to fix compilation problem on windows
  Don't disable core on signal just becasue platform doesn't handle stack trace

- When doing join optimization, pre-sort the tables so that they mimic the execution
  order we've had with 'semijoin=off'. 
- That way, we will not get regressions when there are two query plans (the old and the
  new) that have indentical costs but different execution times (because of factors that
  the optimizer was not able to take into account).