history entries.  Lazy deletion isn't smart or useful here.

Backport from 5.1 .


include/my_sys.h:
  Prepare for rename in 5.1.
mysql-test/r/profiling.result:
  Backport tests from 5.1.
mysql-test/t/profiling.test:
  Backport tests from 5.1.
sql/mysql_priv.h:
  Backport changes from 5.1 .
sql/sp_head.cc:
  Backport changes from 5.1 .
sql/sql_class.cc:
  Backport changes from 5.1 .
sql/sql_parse.cc:
  Backport changes from 5.1 .
sql/sql_profile.cc:
  Push history-limiting code until after the code that adds new 
  history entries.  Lazy deletion isn't smart or useful here.
  
  Correct for 5.0 member existance and execution.
sql/sql_profile.h:
  Backport changes from 5.1 .
sql/sql_show.cc:
  Backport changes from 5.1 .