Bugzilla bug 200162: pass 0 as the third and fourth arguments to sem_open

to work around a bug in sem_open on HP-UX 11.23 or earlier.  The patch is
contributed by Grace Lu of HP.  r=wtc.

nsprpub/pr/src/pthreads/ptsynch.c

@@ -714,7 +714,12 @@ PR_IMPLEMENT(PRSem *) PR_OpenSemaphore(
     }
     else
     {
+#ifdef HPUX
+        /* Pass 0 as the mode and value arguments to work around a bug. */
+        sem->sem = sem_open(osname, 0, 0, 0);
+#else
         sem->sem = sem_open(osname, 0);
+#endif
     }
     if ((sem_t *) -1 == sem->sem)
     {