Description

   This routine destroys a mutex attributes object-that is, the
   object becomes uninitialized. Call this routine when your program
   no longer needs the specified mutex attributes object.

   After this routine is called, the Threads Library may reclaim
   the storage used by the mutex attributes object. Mutexes that
   were created using this attributes object are not affected by the
   destruction of the mutex attributes object.

   The results of calling this routine are unpredictable, if the
   attributes object specified in the attr argument does not exist.