Fix for bug #24117 "server crash on a FETCH with a cursor on a table which is not in the table cache"

Problem:
When creating a temporary field for a temporary table in create_tmp_field_from_field(), a resulting field is created as an exact copy of an original one (in Field::new_field()). However, Field_enum and Field_set contain a pointer (typelib) to memory allocated in the parent table's MEM_ROOT, which under some circumstances may be deallocated later by the time a temporary table is used.

Solution:
Override the new_field() method for Field_enum and Field_set and create a separate copy of the typelib structure in there.

into  ymer.(none):/usr/local/mysql/tmp/mysql-5.0-gca

traces in Valgrind (broken libc6-dbg).
Installing libc6-dbg on Debian will still provide proper bactraces, even
without setting LD_LIBRARY_PATH explicitly.

into  mysql.com:/usr/home/ram/work/bug21789/my41-bug21789

into  mysql.com:/usr/home/ram/work/bug21789/my50-bug21789

into  mysql.com:/usr/home/ram/work/bug21789/my50-bug21789

into  mysql.com:/usr/home/ram/work/bug22029/my50-bug22029

into  mysql.com:/usr/home/ram/work/bug22029/my41-bug22029

into  mysql.com:/usr/home/ram/work/bug22029/my50-bug22029

- Use more appropriate test case.

- Post Merge Fix.

into  mysql.com:/usr/home/ram/work/bug22029/my50-bug22029

- Client side readline functions unconditionally search for Unix '\n' line
endings. In this case, the delimiter statement was set to '//\r' instead 
of the intended '//'. When removing the '\n' check for and remove 
preceeding '\r' character as well.

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint

into  neptunus.(none):/home/msvensson/mysql/mysql-4.1-maint

columns to make sure they both exist and have the intended type 

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint

mysql_fix_privilege_tables.s's ability to convert the system tables as of
3.20 to current system table format
Add similar test for 4.1.23 tables - but use "mysql < mysql_fix_privilege_tables.sql"
so it can be run on any platform. 

into  shellback.(none):/home/msvensson/mysql/mysql-4.1-maint

into  shellback.(none):/home/msvensson/mysql/mysql-5.0-maint

into  shellback.(none):/home/msvensson/mysql/mysql-5.0-maint

"Y" are different) to utf8_general_ci (where same).

$MYSQLTEST_VARDIR, for usage of vardir=e:/var<nnn> on windows

into  neptunus.(none):/home/msvensson/mysql/mysql-4.1-maint

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint

Update usage description

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint

into  neptunus.(none):/home/msvensson/mysql/mysql-5.0-maint

 - Set environment variable BIG_TEST when using --big-test
 - Skip comment lines when looking for features a test case supports.

 - Dont require restart when using extern and there is no record of
   master being started(pid is not known)