An unnecessarily restrictive lock were taken on sub-SELECTs during DELETE.

During parsing, a global structure is reused for sub-SELECTs and the attribute
keeping track of lock options were not reset properly.
This patch introduces a new attribute to keep track on the syntactical lock
option elements found in a sub-SELECT and then sets the lock options accordingly.

Now the sub-SELECTs will try to acquire a READ lock if possible
instead of a WRITE lock as inherited from the outer DELETE statement.


mysql-test/r/lock.result:
  Added test case for bug39843
mysql-test/t/lock.test:
  Added test case for bug39843
sql/sql_lex.cc:
  * Reset member variable lock_option on each new query.
sql/sql_lex.h:
  * Introduced new member variable 'lock_option' which is keeping track
    of the syntactical lock option of a (sub-)select query.
sql/sql_parse.cc:
  * Wrote comments to functions.
sql/sql_yacc.yy:
  * Introduced an attribute to keep track of syntactical lock options
    in sub-selects.
  * Made sure that the default value TL_READ_DEFAULT is at the begining
    of each subselect-rule.

            
The query cache module did not check for the SQL_NO_CACHE keyword before
attempting to query the hash lookup table. This had a small performance impact.

By introducing a check on the query string before obtaining the hash mutex
we can gain some performance if the SQL_NO_CACHE directive is used often.


sql/sql_cache.cc:
  * Introduced new helper function, has_no_cache_directive, for checking the
    existance of a SQL_NO_CACHE directive before actual parsing of the query.

return no rows

The algorithm of determining the best key for loose index scan is doing a loop
over the available indexes and selects the one that has the best cost.
It retrieves the parameters of the current index into a set of variables.
If the cost of using the current index is lower than the best cost so far it 
copies these variables into another set of variables that contain the 
information for the best index so far.
After having checked all the indexes it uses these variables (outside of the 
index loop) to create the table read plan object instance.
The was a single omission : the key_infix/key_infix_len variables were used 
outside of the loop without being preserved in the loop for the best index 
so far.
This causes these variables to get overwritten by the next index(es) checked.
Fixed by adding variables to hold the data for the current index, passing 
the new variables to the function that assigns values to them and copying 
the new variables into the existing ones when selecting a new current best 
index.
To avoid further such problems moved the declarations of the variables used 
to keep information about the current index inside the loop's compound 
statement.

mysql-test/r/group_min_max.result:
  Bug #41610: test case
mysql-test/t/group_min_max.test:
  Bug #41610: test case
sql/opt_range.cc:
  Bug #41610: copy the infix data for the current best index

Some variable values were missing and perl constructs failed.

Initialized the variables and refactored the gcov functions.


.bzrignore:
  Bug#40446 - mysql-test-run --gcov is broken
  Added gcov log files.
mysql-test/lib/mtr_gcov.pl:
  Bug#40446 - mysql-test-run --gcov is broken
  Refactored the gcov functions.
mysql-test/mysql-test-run.pl:
  Bug#40446 - mysql-test-run --gcov is broken
  Initialized gcov variables.
  Added usage information.

Added ORDER BY clause to I_S query to ensure consistent order.
There were differences between 5.1 and 6.0 output.  Correcting it 5.1.

Fixed a warning in 5.1 caused by missing type cast.

of a view are selected by * wildcard

Backported a part of the fix for 36086 to 5.0

mysql-test/r/view_grant.result:
  Bug #41354: test case
mysql-test/t/view_grant.test:
  Bug #41354: test case
sql/sql_acl.cc:
  Bug #41354: return table error when no access and *
sql/sql_base.cc:
  Bug #41354: backported the check in bug 36086 to 5.0

Fixed a typo in the bug fix patch.

sql/share/errmsg.txt:
  - Reserve released error codes in 5.1

Started fix in 5.0 as the same issue is here.
Revising queries used given what appears to be the scope of this test to only select the manipulated variables.
Added tests for values that are / are not multiples of 1024 to test rounding / constraints.
This behavior is not currently documented (docs bug has been opened)

*with --with-charset=utf8*

Problem: wrong LONG TEXT field length is sent to a client 
when multibyte server character set used.

Fix: always limit field length sent to a client to 2^32,
as we store it in 4 byte slot.

Note: mysql_client_test changed accordingly.


sql/protocol.cc:
  Fix for bug#19829:make test Failed in mysql_client_test 
  *with --with-charset=utf8*
    - limit field length sent to client to UINT_MAX32 as 
      it may exceeds 32 bit slot for LONG TEXT fields if
      thd_charset->mbmaxlen > 1.
tests/mysql_client_test.c:
  Fix for bug#19829:make test Failed in mysql_client_test
  *with --with-charset=utf8*
    - checking field members have in mind that field length
      is limited to UINT_MAX32.

usermode address space limit.

Fix: use /LARGEADDRESSAWARE link option when linking 32 bit
executables

bug#43111

print compact view name if the view belongs to the current database


mysql-test/r/information_schema_db.result:
  result fix
mysql-test/r/mysqldump.result:
  result fix
mysql-test/r/view_grant.result:
  result fix
sql/sql_show.cc:
  print compact view name if the view belongs to the current database