into  vajra.(none):/opt/local/work/mysql-5.1-runtime

streamline the event worker thread work flow and try to eliminate
possibilities for memory corruptions that might have been
lurking in previous (complicated) code.
This patch: 
 * removes Event_job_data::compile that was never used
 * cleans up Event_job_data::execute to minimize juggling with
   thread context and eliminate unneded code paths
 * Implements Security_context::change/restore_security_context
   to be able to re-use these methods in all stored programs
This is to maybe fix Bug#27733 "Valgrind failures in 
remove_table_from_cache".
Review comments applied.

into  trift2.:/MySQL/M51/push-5.1

into  trift2.:/MySQL/M50/push-5.0

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.0-build-work

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.1-build

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.1-build-work

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.1-build-work

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.0-build-work

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.0-build-work

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.1-build

into  mysql.com:/home/kent/bk/tmp3/mysql-4.1-build

into  mysql.com:/home/kent/bk/tmp3/mysql-5.0-build

into  mysql.com:/home/kent/bk/tmp3/mysql-5.1-build

into  mysql.com:/home/kent/bk/tmp3/mysql-5.1-build

  Back port of include change and copyright from 5.1
Makefile.am, zlib.m4:
  Use separate libtool convenience library for the bundled
  zlib to embed into executables and shared libraries created,
  and one to install into the pkglib directory

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.1-build-work

into  mysql.com:/d2/hf/mrg/mysql-5.1-opt

into  mysql.com:/d2/hf/mrg/mysql-5.0-opt

into  mysql.com:/d2/hf/mrg/mysql-5.1-opt

into  mysql.com:/d2/hf/mrg/mysql-5.1-opt

into  mysql.com:/d2/hf/mrg/mysql-5.0-opt

into  mysql.com:/home/kent/bk/tmp4/mysql-5.1-engines

into  mysql.com:/home/kent/bk/tmp4/mysql-5.0-engines

into  moonbone.local:/mnt/gentoo64/work/27586-bug-5.0-opt-mysql

into  naruto.:C:/cpp/mysql-5.1-runtime

into  trift2.:/MySQL/M41/push-4.1

into  trift2.:/MySQL/M50/push-5.0

into  trift2.:/MySQL/M51/push-5.1

into  mysql.com:/d2/hf/mrg/mysql-5.1-opt

into  mysql.com:/d2/hf/mrg/mysql-5.1-opt

into  mysql.com:/d2/hf/mrg/mysql-5.1-opt

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.1