Background: In some thread implementations, pthread_once functions execute in a
separate thread from the one that called it. Some GSSAPI functions call
pthread_once to ensure that the GLOBUS_GSI_GSSAPI_MODULE is activated before
doing their processing. The globus_module_activate function uses a recursive
mutex so that it can keep track of dependencies between modules when doing
deactivation.

If a module (from it's activation function) calls a gssapi function, the
application can deadlock. The threads deadlock like this:

Thread 1:
activate (lock module activation lock)
  gss_*
  pthread_once

----
Thread 2:
once_function
  globus_module_activate: attempt to lock module activation lock 

This will only happen if the gss function is the first one which attempts to
use the pthread_once control in GSSAPI.