Don't block SIGINT (Control-C) when --gdb is passed to mysqld.
Was broken at least on OS X.

(kudos to Mattias Jonsson)


sql/mysqld.cc:
  Don't block SIGINT when TEST_SIGINT (--gdb) is used, even if
  thr_kill_signal is some other signal (SIGUSR2) and
  pthread_sigmask() in signal_hand() isn't good enough.