Problem: mysqlbinlog_base64 failed sporadically.

Reason: Missing "flush logs" before running $MYSQL_BINLOG,
which could start dumping the log file before server
has finished writting into it.
Fix:
- implementing --force-if-open option to "mysqlbinlog"
- adding --disable-force-if-open to make $MYSQL_BINLOG
  fail on non-closed log files, to garantee that nobody
  will forget "flush logs" in the future.
- adding "flush logs" into all affected tests.

into  mysql.com:/usr/home/bar/mysql-5.1.b20396v2

into  romeo.(none):/home/bkroot/mysql-5.1-new-rpl

into  mysql.com:/home/bk/MERGE/mysql-5.1-merge

into  mysql.com:/home/bk/MERGE/mysql-5.0-merge

into  mysql.com:/home/bk/MERGE/mysql-5.1-merge

into  mysql.com:/home/bk/MERGE/mysql-5.0-merge

into  mysql.com:/home/bk/MERGE/mysql-4.1-merge

into  quant.(none):/ext/mysql/bk/mysql-5.0-bug24507

into  mysql.com:/usr/home/bar/mysql-5.1.b20396

into  mysql.com:/usr/home/bar/mysql-5.0.b24158

into  quant.(none):/ext/mysql/bk/mysql-5.0-bug24507

The problem was located to lie inside current NPTL pthread_exit() 
implementation. Race conditions in this code can lead to segmentation
fault. Hovewer, this can happen only in a race between first thread 
calling pthread_exit() and other threads. 

Workaround implemented in this patch spawns a dummy thread, which
exits immediately, during thread lib initialization. This will exclude
segment violations when further threads exit.
 

into  mysql.com:/usr/home/bar/mysql-5.0.b20396

into  suse.vabb.com:/home/Chuck/development/mysql-5.1_WL_3618

Please see worklog for details on files changed.

into  example.com:/work/mysql-5.1-maint

into  neptunus.(none):/home/msvensson/mysql/mysql-5.1-maint

Remove DBUG_ENTER in my_end

uninitialized list of guarded instances.

into  neptunus.(none):/home/msvensson/mysql/mysql-5.1-maint

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

into  neptunus.(none):/home/msvensson/mysql/mysql-5.1-maint

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

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

into  neptunus.(none):/home/msvensson/mysql/mysql-5.1-maint

into  neptunus.(none):/home/msvensson/mysql/mysql-5.1