Update NSPR to 4.12 and NSS to 3.23 on iOS

nspr/pr/include/md/_unixos.h

 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef prunixos_h___
 #define prunixos_h___
 
 /*
  * If FD_SETSIZE is not defined on the command line, set the default value
@@ skipping 284 matching lines @@
 /************************************************************************/
 
 #ifdef _MD_INTERVAL_USE_GTOD
 extern PRIntervalTime   _PR_UNIX_GetInterval(void);
 extern PRIntervalTime   _PR_UNIX_TicksPerSecond(void);
 #define _MD_INTERVAL_INIT()
 #define _MD_GET_INTERVAL                _PR_UNIX_GetInterval
 #define _MD_INTERVAL_PER_SEC            _PR_UNIX_TicksPerSecond
 #endif
 
-#ifdef HAVE_CLOCK_MONOTONIC
+#ifdef _PR_HAVE_CLOCK_MONOTONIC
 extern PRIntervalTime   _PR_UNIX_GetInterval2(void);
 extern PRIntervalTime   _PR_UNIX_TicksPerSecond2(void);
 #define _MD_INTERVAL_INIT()
 #define _MD_GET_INTERVAL                _PR_UNIX_GetInterval2
 #define _MD_INTERVAL_PER_SEC            _PR_UNIX_TicksPerSecond2
 #endif
 
 #define _MD_INTERVAL_PER_MILLISEC()     (_PR_MD_INTERVAL_PER_SEC() / 1000)
 #define _MD_INTERVAL_PER_MICROSEC()     (_PR_MD_INTERVAL_PER_SEC() / 1000000)
 
@@ skipping 299 matching lines @@
 {
     _MD_Open64 _open64;
     _MD_Mmap64 _mmap64;
     _MD_Stat64 _stat64;
     _MD_Fstat64 _fstat64;
     _MD_Lseek64 _lseek64;
 };
 extern struct _MD_IOVector _md_iovector;
 
 #endif /* prunixos_h___ */