DROP/CREATE SCHEMA, CREATE TABLE, REPAIR.

The cause of assert was concurrent execution of
DROP DATABASE and REPAIR TABLE where first statement
deleted table's file .TMD at the same time as
REPAIR TABLE tried to read file details from the old file
that was just removed.

Additionally was fixed trouble when DROP TABLE try delete
all files belong to table being dropped at the same time
when REPAIR TABLE statement has just deleted .TMD file.

No regression test added because this would require adding a
sync point to mysys/my_redel.c. Since this bug is not present in
5.5+, adding test coverage was considered unnecessary.
The patch has been verified using RQG testing.


sql/sql_db.cc:
  mysql_rm_known_files() modified: ignore possible ENOENT error
  when trying delete all table's files. Such aggressive 
  algorithm permits skip already deleted (in another thread)
  files.
  
  Installation of Drop_table_error_handler as internal error handler
  moved from mysql_rm_db() to mysql_rm_knowns_files() near to place
  where source of possible errors (call to mysql_rm_table_part2) located.
storage/myisam/mi_check.c:
  mi_repair() was modified: set param->retry_repair= 0
  in order to don't call following failover procedure
  in ha_myisam::repair().

mysqltest checks if the stmt is one that should be run in ps mode,
  but regexp doesn't match if preceeded by /* */ comment.
Fix: match function will jump over /*..*/ if found at start

Backported use of setenv() from 5.5
This will remove the leak on systems that have setenv()
I have not fixed the string.c leak, it's a local variable
   that the cleanup function cannot access.

Fixed some errors
Added note about 'no' prefix to options
See also follow-up comment to bug report

Workaround: add --loose-skip-innodb-use-native-aio
Only on linux if explicitly using --mem or setting $OPT_MEM

Add check that there is a RHS of the expression
Added to mysqltest.test

Var's string value was not 0-terminated if intially null.
While at it, also removed some reported memory leaks
Added sanity check, setting val_len=0 if val==0

Added option --debug-common which sets 'd' debug flags to the suggested list

 my_seek() and my_tell() functions now honour MY_WME flag.


include/mysys_err.h:
  Fix for bug#48451: my_seek and my_tell ignore MY_WME flag
    - EE_CANT_SEEK added, used in my_seek() and my_tell() functions.
mysys/errors.c:
  Fix for bug#48451: my_seek and my_tell ignore MY_WME flag
    - EE_CANT_SEEK added, used in my_seek() and my_tell() functions.
mysys/my_seek.c:
  Fix for bug#48451: my_seek and my_tell ignore MY_WME flag
    - my_seek() and my_tell() handle MY_WME flag.
mysys/my_symlink.c:
  Fix for bug#48451: my_seek and my_tell ignore MY_WME flag
    - __attribute__((unused)) removed, as myf MyFlags is
  actually used in the my_realpath() function.
storage/myisam/ha_myisam.cc:
  Fix for bug#48451: my_seek and my_tell ignore MY_WME flag
    - check my_seek() result.

 when semijoin=on

When setting the aggregate function as having no rows to report
the function no_rows_in_result() was calling Item_sum::reset().
However this function in addition to cleaning up the aggregate 
value by calling aggregator_clear() was also adding the current
value to the aggregate value by calling aggregator_add().
Fixed by making no_rows_in_result() to call aggregator_clear()
directly.
Renamed Item_sum::reset to Item_sum::reset_and_add() to
and added a comment to avoid misinterpretation of what the
function does.

Before this fix, the output of SHOW ENGINE PERFORMANCE_SCHEMA STATUS
used uppercase to name performance schema tables.

This is inconsistent since performance schema tables have been renamed to lowercase.

Also, an old table 'PROCESSLIST' was still visible, 
even after this table got renamed to 'threads'.

This fix:
- correctly uses lowercases in the output, to match the current naming.
- replaced 'PROCESSLIST' with 'threads'.

Tested the output of SHOW ENGINE PERFORMANCE_SCHEMA STATUS manually.
No automated test cases can be written for this, 
since the output is too platform dependent (sizes).

merged from mysql-5.5.8-release tree,
revision: ramil@mysql.com-20101203174908-217tdkn150vieha9

when there was one NULL value, AVG(DISTINCT) could forget about other values.
See commit comment of item_sum.cc.

mysql-test/r/func_group.result:
  before the code fix, both SELECTs would return NULL
sql/item_sum.cc:
  Assume we are executing "SELECT AVG([DISTINCT] some_field) FROM some_table".
  and some_field is the single field of some_table for simplicity.
  Each time a row is processed (evaluate_join_record()->
  end_send_group()->update_sum_func()) an aggregator is notified,
  which itself notifies an Item_sum_avg.
  Without DISTINCT, this Item_sum_avg immediately increments its
  internal "sum of values" and "count of values" (the latter being
  Item_sum_avg::count). The count is incremented only if the row's value
  is not NULL (in Item_sum_avg::add()), per AVG() semantices. This row's value
  is available in args[0] of Item_sum_avg ("args[0]" stands for
  "the first argument of the item": it's an Item_field which automatically
  receives the row's value when a row is read from the table).
  bool Item_sum_avg::add()
  {
    if (Item_sum_sum::add()) << calculates the sum (ignores NULL)
      return TRUE;
    if (!args[0]->null_value)<<if added value is not NULL
      count++;       <<increment "count"
    return FALSE;
  }
  and everything works.
  With DISTINCT, when a row is processed by evaluate_join_record(),
  Item_sum_avg does no immediate computation, rather stores
  the row's value in a tree (to throw the value away if it is a duplicate
  of previous value, otherwise to remember all
  distinct values). It's only when it's time to send the average to the
  user (at end of the query:
  sub_select(end_of_records=true)->end_send_group()->
  select_send->send_data()->Protocol::send_result_set_row()->
  Item::send()->Item_sum_avg->val_str()), that we iterate over the tree,
  compute the sum and count: for this, for each element of the tree,
  Item_sum_avg::add() is called and has the same two steps as before:
  * Item_sum_sum::add() updates the sum (finding the tree element's value
  correctly, and determining correctly its NULLness - look for "arg_is_null"
  in that function)
  * the "if (!args[0]->null_value)" test right after, breaks: it uses args[0],
  which isn't the tree's element but rather the value for the last row
  processed by evaluate_join_record(). So if that last row was NULL,
  "count" stays 0 for each row, and AVG() then returns NULL (count==0 =>
  NULL, per AVG() semantics).
  The fix is to let the aggregator tell whether the value
  it just saw was NULL. The aggregator knows where to get the info
  thanks to virtual functions. Item_sum_sum::add() now asks
  the aggregator. Item_sum_avg() also asks the aggregator
  and then knows it shouldn't increment "count".
sql/item_sum.h:
  Aggregator can now tell about value/NULLness of just-aggregated value

Do not use the same maintainer mode flags for both GCC and ICC.
The -Wall option for ICC enables more warnings than its GCC
counterpart.

Null merge to from mysql-5.1-bugteam to mysql-5.5-bugteam.
Test case does not exist in 5.5 tree.

Automerging bzr bundle from bug report into latest 
mysql-5.1-bugteam.

            command line clients.

Command line tools like mysqladmin and mysqldump did not recognize
default-auth and plugin-dir options.

Support for these options was found missing in these command line
tools.

Fixed by adding support for the same.


client/mysqladmin.cc:
  Bug#58139 : default-auth option not recognized in MySQL standard
              command line clients.
  
  Introduced two new variables to hold values from default-auth and
  plugin-dir options and further pushed them to client's st_mysql
  instance.
client/mysqldump.c:
  Bug#58139 : default-auth option not recognized in MySQL standard
              command line clients.
  
  Introduced two new variables to hold values from default-auth and
  plugin-dir options and further pushed them to client's st_mysql
  instance.
mysql-test/r/plugin_auth.result:
  Added test case for Bug#58139.
mysql-test/t/plugin_auth.test:
  Added test case for Bug#58139.

Re-enable fast mutexes on Linux for release builds.

to_binlog -> binlog_stmt.

Adding symbol FN_DIRSEP to Windows as well.

Fixing test case that fails on Windows because .dll is used.