Added option --gdb
Free memory used by replicate_xxx and binglog_xxx options


mysql-test/mysql-test-run.sh:
  Added --gdb when using gdb
mysys/thr_alarm.c:
  Safety check
sql/mysql_priv.h:
  Don't install signal handler for SIGINT by default
sql/mysqld.cc:
  Don't install signal handler for SIGINT by default
  Added option --gdb
  Free memory used by replicate_xxx and binglog_xxx options.
  Add statistics variable for killed threads
sql/repl_failsafe.cc:
  Incremented aborted_connects on failure
sql/sql_list.cc:
  Added free_list() to free memory on shutdown.