Bug#47633 - assert in ha_myisammrg::info during OPTIMIZE
 
   The server crashed on an attempt to optimize a MERGE table with
   non-existent child table.
 
   mysql_admin_table() relied on the table to be successfully open
   if a table object had been allocated.
 
   Changed code to check return value of the open function before
   calling a handler:: function on it.

NOTE: backporting BUG#42150 into next-mr
      Includes latest Andrei's patch (see [2 Feb 18:40] Bugs System)
      and merge.test post-push fix (see [3 Feb 18:04] Bugs System)

The reason of the bug appeared to be overreacting on absense of a
binlog file although the file name had been presented in in the master
binlog index file.
By convention, there should have been only a warning printed and the rest of
`reset master' logics completed.  This did not happen on windows
due to incorrect value of my_errno returned from nt_share_delete().
      
Fixed with correcting my_errno assignment in nt_share_delete() to be ENOENT in 
he event of no binlog file. Some minor refactoring has been made.

Revision: 
2597.72.1 revid:sp1r-Reggie@core.-20080403153947-15243
removed instances of __NT__ from code. We now only build "NT" binaries

            corrupts a MERGE table

Post-pushbuild fix. The merge test failed on Windows.
The MoveFile() function returned the error code
ERROR_ACCESS_DENIED.

The fix is to use a different name for the file to be
deleted. This is the same trick as we use for the error
code ERROR_ALREADY_EXISTS.

Added ERROR_ACCESS_DENIED to the list of error codes that
require to change the name of the file to be deleted.

- Reserver namespace and place in frm for TABLE_CHECKSUM and PAGE_CHECKSUM create options
- Added syncing of directory when creating .frm files
- Portability fixes
- Added missing cast that could cause bugs
- Code cleanups
- Made some bit functions inline
- Moved things out of myisam.h to my_handler.h to make them more accessable
- Renamed some myisam variables and defines to make them more globaly usable (as they are used outside of MyISAM)
- Fixed bugs in error conditions
- Use compiler time asserts instead of run time
- Fixed indentation
HA_EXTRA_PREPARE_FOR_DELETE -> HA_EXTRA_PREPARE_FOR_DROP as the old name was wrong
(Added a define for old value to ensure we don't break any old code)
Added HA_EXTRA_PREPARE_FOR_RENAME as a signal for rename (before we used a DROP signal which is wrong)
- Initialize error messages early to get better errors when mysqld or an engine fails to start
- Fix windows bug that query_performance_frequency was not initialized if registry code failed
- thread_stack -> my_thread_stack_size

  Changed header to GPL version 2 only

 and BUG#19208 "Test 'rpl000017' hangs on Windows".
 Both bugs are caused by attempting to delete an opened
 file and to create immediatedly a new one with the same
 name. On Windows it can be supported only on NT-platforms
 (by using FILE_SHARE_DELETE mode and with renaming the
 file before deletion). Because deleting not-closed files
 is not supported on all platforms (e.g. Win 98|ME) this
 is to be considered harmful and should be eliminated by
 a "code redesign".

Fixed memory leak on shutdown (Affects the embedded version & MyODBC)

Fixed error number handling bug in mysqltest.
Fixed that error number from insert delayed is reported correctly.
merged new vio code with old violite code.