- Only use the "hack for bug in NTPL" if using NTPL, by dynamically
   checking the thd_lib_detected flag


mysys/my_thr_init.c:
  Only start the "dummy thread hack for bug in NPTL" - if using NPTL.
  If the system uses LinuxThreads it's not needed, it actually causes 
  the "pthread manager" to be started as root and thus all subsequent
  threads will also run as root although mysqld drops root privileges, 
  this in turns causes mysqld to deadlock since the mysqlds main thread
  running as <user> can't send signals to a process owned by root.