Column names weren't checked for uniqueness for subqueries.

Code for names uniqueness checking used for view creation moved into 
separate function named check_duplicate_names(). It's called on 
preparation of subqueries to check uniqueness of names. If duplicate names 
are found then error is raised.

into  mysql.com:/usr/local/home/marty/MySQL/mysql-5.0

into  mysql.com:/usr/local/home/marty/MySQL/mysql-5.0

into  alpha.xl.local:/home/schwenke/Work/MySQL/BK-internal-tree/mysql-5.0

Review of new pushed code

into  mishka.local:/home/my/mysql-5.0

into  alpha.xl.local:/home/schwenke/Work/MySQL/BK-internal-tree/mysql-5.0

into rurik.mysql.com:/home/igor/dev/mysql-5.0-0

  Modified test case for bug #12144.

into  mishka.local:/home/my/mysql-5.0

Change bool in C code to my_bool
Added to mysqltest --enable_parsning and --disable_parsing to avoid to have to comment parts of tests
Added comparison of LEX_STRING's and use this to compare file types for view and trigger files.

into rurik.mysql.com:/home/igor/mysql-4.1

If GROUP_CONCAT is calculated we always put its argument into a temp
table, even when the argument is a constant item.

into rurik.mysql.com:/home/igor/dev/mysql-5.0-0

into  sanja.is.com.ua:/home/bell/mysql/bk/work-trigger-5.0

into lmy002.wdf.sap.corp:/home/georg/work/mysql/prod/mysql-5.0

into  sanja.is.com.ua:/home/bell/mysql/bk/work-trigger-5.0

into  mysql.com:/home/jimw/my/mysql-5.0-clean

into lmy002.wdf.sap.corp:/home/georg/work/mysql/prod/mysql-5.0

macro floatget was missing in config-win.h

  (thanks to JoergB for spotting it)

  Added a test case for bug #12095.
sql_class.h:
  Fixed bug #12095: a join query with GROUP_CONCAT over a single row table.
  Added a flag to the TMP_TABLE_PARAM class forcing to put constant
  items generated after elimination of a single row table into temp table
  in some cases (e.g. when GROUP_CONCAT is calculated over a single row
  table).
  bk ci sql/item_sum.cc
  Fixed bug #12095: a join query with GROUP_CONCAT over a single row table.
  If GROUP_CONCAT is calculated we always put its argument into a temp
  table, even when the argument is a constant item.
sql_select.cc:
  Fixed bug #12095: a join query with GROUP_CONCAT over one row table.
  If temp table is used to calculate GROUP_CONCAT the argument should
  be always put into this table, even when it is a constant item.

Before the fix in ~Prepared_statments we got a memory leak when executing mysql_client_test.test
Note that test 'variables.test' fails.
This will be fixed when Jimw pushes the fix for Bug 10351

into  mysql.com:/home/my/mysql-5.0

allowed unintended overflows. (Bug #10351)

  Made the test case for bug #12144 independent on other tests.

into  mysql.com:/home/my/mysql-5.0

into mysql.com:/home/psergey/mysql-5.0-28jul-look

  Modified the test case for patch of the bug #12144
  to display status of Handler_read_next before and
  after the tested query.