Fixed bug in RAND() usage in mysqlbinlog


configure.in:
  Added detection if pthread_attr_getstacksize() exists
include/thr_lock.h:
  Fixed wrong comment
sql/log_event.cc:
  Fixed bug in RAND() usage in mysqlbinlog
sql/mysqld.cc:
  Portablity fix
sql/repl_failsafe.cc:
  Set host_or_ip for system threads (to make other code simpler)
sql/slave.cc:
  Set host_or_ip for system threads (to make other code simpler)
sql/sql_class.cc:
  Set host_or_ip for system threads (to make other code simpler)
sql/sql_insert.cc:
  Set host_or_ip for system threads (to make other code simpler)
sql/sql_show.cc:
  Set host_or_ip for system threads (to make other code simpler)