More debugging variables
Increment aborted_threads in case of killed or too big packet


include/thr_alarm.h:
  made prototype more portable
mysys/thr_alarm.c:
  Print error if we can't delete an alarm
sql/mysqld.cc:
  Statistics variable (for debugging)
sql/net_serv.cc:
  statistics variable (for debugging)
sql/sql_parse.cc:
  Increment aborted_threads in case of killed or too big packet