rb://566
approved by: Sunny

When using native aio on linux each IO helper thread should be able to
handle upto 256 IO requests. The number 256 is the same which is used
for simulated aio as well. In case of windows where we also use native
aio this limit is 32 because of OS constraints. It seems that we are
using the limit of 32 for all the platforms where we are using native
aio. The fix is to use 256 on all platforms except windows (when native
aio is enabled on windows)

This change was backported from 5.5.

This warning also happens in 5.1 with a slightly different codepath.

used (--with-zlib-dir=bundled) then there is no libz.so involved.

Suppress a bogus valgrind warning.

The bug would cause a crash of InnoDB if a non-standard or unknown table
flags existed in a SYS_TABLES record. This is important because the next
file version, Cheetah, will identify itself by expanding this field.  So
unless this is fixed, an older engine that tries to open a table in a
tablespace with a newer file version will crash instead of report an error
and refuse to open the table, as it should do.

Reviewed at RB://583.    Approved by Marko.

Add suppressions for a bogus valgrind warnings.

btr_rec_get_field_ref_offs(), btr_rec_get_field_ref(): New functions.
Get the pointer to an externally stored field.

btr_cur_set_ownership_of_extern_field(): Assert that the BLOB has not
already been disowned.

btr_store_big_rec_extern_fields(): Rename to
btr_store_big_rec_extern_fields_func() and add the debug parameter
update_in_place. All pointers to externally stored columns in the
record must either be zero or they must be pointers to inherited
columns, owned by this record or an earlier record version. For any
BLOB that is stored, the BLOB pointer must previously have been
zero. When the function completes, all BLOB pointers must be nonzero
and owned by the record.

rb://549 approved by Jimmy Yang

row_purge(): Change the return type to void. (The return value always
was DB_SUCCESS.) Remove some local variables.

row_undo_mod_remove_clust_low(): Remove some local variables.

rb://547 approved by Jimmy Yang

Antelope files in btr_check_blob_fil_page_type(). Unfortunately, we
must keep the check in production builds, because InnoDB wrote
uninitialized garbage to FIL_PAGE_TYPE until fairly recently (5.1.x).

rb://546 approved by Jimmy Yang

It was the enabling of UNIV_DEBUG_FILE_ACCESSES that caught Bug #55284
in the first place. This is a very light piece of of debug code, and
there really is no reason why it is not enabled in all debug builds.

rb://551 approved by Jimmy Yang

This change was originally done in
marko.makela@oracle.com-20101011085943-50pskvsbbsujbukg
but was later lost during the merge process.

trx rollback or purge

This patch does not relax the failing debug assertion during purge.
That will be revisited once we have managed to repeat the assertion failure.

row_upd_changes_ord_field_binary_func(): Renamed from
row_upd_changes_ord_field_binary(). Add the parameter que_thr_t* in
UNIV_DEBUG builds. When the off-page column cannot be retrieved,
assert that the current transaction is a recovered one and that it is
the one that is currently being rolled back.

row_upd_changes_ord_field_binary(): A wrapper macro for
row_upd_changes_ord_field_binary_func() that discards the que_thr_t*
parameter unless UNIV_DEBUG is defined.

row_purge_upd_exist_or_extern_func(): Renamed from
row_purge_upd_exist_or_extern(). Add the parameter que_thr_t* in
UNIV_DEBUG builds.

row_purge_upd_exist_or_extern(): A wrapper macro for
row_purge_upd_exist_or_extern_func() that discards the que_thr_t*
parameter unless UNIV_DEBUG is defined.

Make trx_roll_crash_recv_trx const. If there were a 'do not
dereference' attribute, it would be appropriate as well.

rb://588 approved by Jimmy Yang

Third updated patch - this version also includes copyright notice in added Perl script.
This patch implements a check for such modules at runtime. If modules are not found or unable to load, the test is skipped with 
the following message:
            
            [ skipped ]  Test needs Perl modules DBI and DBD::mysql
            
Checks are done via a helper Perl script which looks for the module in a runtime environment that is as similar to that of the 
mysqlhotcopy script as possible (thus not intended for Windows environments at this time).
The helper script tells mysql-test about the result by writing information to a temporary file that is later read by mysql-test.
See comments in added files (have_dbi_dbd-mysql.inc and checkDBI_DBD-mysql.pl) for details.
The patch also removes the mysqlhotcopy tests from the list of disabled tests.

Do as mysqld_safe: if running mysqld-debug, plugins are in debug subdirs
NB mtr --debug won't work in this context until 47141 is fixed
Also moved read_plugin_defs; no point running this in all worker threads

rb://582 approved by Marko

for external_size
      
rb://581 approved by Marko