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.

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.

 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.

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.

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.