backporting WL#2934.

                      to string conversions and vice versa" 
Initial import of the dtoa.c code and custom wrappers around it 
to allow its usage from the server code. 
 
Conversion of FLOAT/DOUBLE values to DECIMAL ones or strings 
and vice versa has been significantly reworked. As the new 
algoritms are more precise than the older ones, results of such 
conversions may not always match those obtained from older 
server versions. This in turn may break compatibility for some 
applications. 
 
This patch also fixes the following bugs: 
- bug #12860 "Difference in zero padding of exponent between 
Unix and Windows" 
- bug #21497 "DOUBLE truncated to unusable value" 
- bug #26788 "mysqld (debug) aborts when inserting specific 
numbers into char fields" 
- bug #24541 "Data truncated..." on decimal type columns 
without any good reason" 

Post-merge fix: wait for statement result before disconnecting. Otherwise the statement might affect unrelated tests. mysql-test/t/lock_multi.test, Reap statement status

Updated suppressed warning messages.

Added extra checks of 64-bit atomic support on GCC and Solaris, also added 64-bit support in solaris.h which was missing

Conflicts:
  - mysys/charset.c
  - mysys/my_thr_init.c

Conflicts:
  - storage/myisam/mi_packrec.c

The test allowed random coincidence of connection ids for two concurrent
sessions performing CREATE/DROP temp tables.

Fixed with correcting the test. The sessions connection ids are not changed
from their defaults anymore.

                  
When compressed myisam files are opened, they are always memory mapped
sometimes causing memory swapping problems.

When we mmap the myisam compressed tables of size greater than the memory 
available, the kswapd0 process utilization is very high consuming 30-40% of 
the cpu. This happens only with linux kernels older than 2.6.9

With newer linux kernels, we don't have this problem of high cpu consumption
and this option may not be required.
 
The option 'myisam_mmap_size' is added to limit the amount of memory used for
memory mapping of myisam files. This option is not dynamic.

The default value on 32 bit system is 4294967295 bytes and on 64 bit system it
is 18446744073709547520 bytes.

Note: Testcase only tests the option variable. The actual bug has be to 
tested manually.

include/my_global.h:
  Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
  
  define SIZE_T_MAX
include/myisam.h:
  Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
  
  declare 'myisam_mmap_size' and 'myisam_mmap_used' variables and the mutex
  THR_LOCK_myisam_mmap
myisam/mi_packrec.c:
  Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
  
  add 'myisam_mmap_size' option which limits the memory available to mmap of 
  myisam files
myisam/mi_static.c:
  Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
  
  declare 'myisam_mmap_size' and 'myisam_mmap_used' variables and the mutex
  THR_LOCK_myisam_mmap
myisam/myisamdef.h:
  Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
  
  move MEMMAP_EXTRA_MARGIN to myisam.h so that it can be used in mysqld.cc
mysql-test/r/variables.result:
  Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
  
  Testcase for BUG#37408 to test the myisam_mmap_size option
mysql-test/t/variables.test:
  Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
  
  Testcase for BUG#37408 to test the myisam_mmap_size option
mysys/my_thr_init.c:
  Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
  
  intialize the lock THR_LOCK_myisam_mmap
sql/mysqld.cc:
  Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
  
  add the 'myisam_mmap_size' option
sql/set_var.cc:
  Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
  
  add the 'myisam_mmap_size' to the SHOW VARIABLES list

returns incorrect results with where

An outer join of a const table (outer) and a normal table
(inner) with GROUP BY on a field from the outer table would
optimize away GROUP BY, and thus trigger the optimization to
do away with a temporary table if grouping was performed on
columns from the const table, hence executing the query with
filesort without temporary table. But this should not be
done if there is a non-indexed access to the inner table,
since filesort does not handle joins. It expects either ref
access, range ditto or table scan. The join condition will
thus not be applied.

Fixed by always forcing execution with temporary table in
the case of ROLLUP with a query involving an outer join. This
is a slightly broader class of queries than need fixing, but
it is hard to ascertain the position of a ROLLUP field wrt
outer join with current query representation.

mysql-test/r/join_outer.result:
  Bug#47650: Test result
mysql-test/t/join_outer.test:
  Bug#47650: Test case
sql/sql_select.cc:
  Bug#47650: Fix

Problem: inserting a record we don't set unused null bits in the
record buffer if no default field values used.
That may lead to wrong live checksum calculation.

Fix: set unused null bits in the record buffer in such cases.


mysql-test/r/myisam.result:
  Fix for bug#49465: valgrind warnings and incorrect live checksum...
    - test result.
mysql-test/t/myisam.test:
  Fix for bug#49465: valgrind warnings and incorrect live checksum...
    - test case.
sql/sql_insert.cc:
  Fix for bug#49465: valgrind warnings and incorrect live checksum...
    - set unused null bits to 1 in the record buffer in case we
  don't call restore_record() before a fill_record() call
  (when no default values used).

The bug is caused by a race condition between the 
INSERT DELAYED thread and the client thread's FLUSH TABLE.  The 
FLUSH TABLE does not guarantee (as is (wrongly) suggested in the 
test case) that the INSERT DELAYED is ever executed.  The 
execution of the test case will thus not be deterministic.

The fix has been to do a deterministic verification that both
threads are complete by checking the content of the table.

Calling push_warning/push_warning_printf with a level of
WARN_LEVEL_ERROR *is* a bug. We should either use my_error(),
or WARN_LEVEL_WARN.

Conflicts:
  - mysql-test/r/select.result
  - mysql-test/t/select.test
  - sql/item_cmpfunc.h
  - sql/sql_show.cc

Conflicts:
  - include/my_no_pthread.h
  - mysql-test/r/sp-ucs2.result
  - sql/log.cc
  - sql/sql_acl.cc
  - sql/sql_yacc.yy