Update NSPR to 4.12 and NSS to 3.23 on iOS

nspr/pr/src/md/unix/unix.c

 /* -*- 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/. */
 
 #include "primpl.h"
 
 #include <string.h>
 #include <signal.h>
 #include <unistd.h>
@@ skipping 2697 matching lines @@
     void *addr, PRSize len, PRIntn prot, PRIntn flags,
     PRIntn fildes, PRInt64 offset)
 {
     PR_SetError(PR_FILE_TOO_BIG_ERROR, 0);
     return NULL;
 }  /* _MD_Unix_mmap64 */
 #endif /* defined(_PR_NO_LARGE_FILES) || defined(SOLARIS2_5) */
 
 /* Android <= 19 doesn't have mmap64. */
 #if defined(ANDROID) && __ANDROID_API__ <= 19
-extern void *__mmap2(void *, size_t, int, int, int, size_t);
+PR_IMPORT(void) *__mmap2(void *, size_t, int, int, int, size_t);
 
 #define ANDROID_PAGE_SIZE 4096
 
 static void *
 mmap64(void *addr, size_t len, int prot, int flags, int fd, loff_t offset)
 {
     if (offset & (ANDROID_PAGE_SIZE - 1)) {
         errno = EINVAL;
         return MAP_FAILED;
     }
@@ skipping 304 matching lines @@
     ticks += (PRUint32)time.tv_usec / PR_USEC_PER_MSEC;  /* so's that */
     return ticks;
 }  /* _PR_UNIX_GetInterval */
 
 PRIntervalTime _PR_UNIX_TicksPerSecond()
 {
     return 1000;  /* this needs some work :) */
 }
 #endif
 
-#if defined(HAVE_CLOCK_MONOTONIC)
+#if defined(_PR_HAVE_CLOCK_MONOTONIC)
 PRIntervalTime _PR_UNIX_GetInterval2()
 {
     struct timespec time;
     PRIntervalTime ticks;
 
     if (clock_gettime(CLOCK_MONOTONIC, &time) != 0) {
         fprintf(stderr, "clock_gettime failed: %d\n", errno);
         abort();
     }
 
@@ skipping 724 matching lines @@
                 rv++;
             }
         }
         PR_ASSERT(rv > 0);
     }
     PR_ASSERT(-1 != timeout || rv != 0);
 
     return rv;
 }
 #endif /* _PR_NEED_FAKE_POLL */