Disable optimization in prdtoa.c under VS2013.

nspr/pr/src/misc/prdtoa.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/. */
 
 /*
  * This file is based on the third-party code dtoa.c.  We minimize our
  * modifications to third-party code to make it easy to merge new versions.
  * The author of dtoa.c was not willing to add the parentheses suggested by
  * GCC, so we suppress these warnings.
  */
 #if (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 2)
 #pragma GCC diagnostic ignored "-Wparentheses"
 #endif
 
+#if _MSC_VER == 1800
+// TODO(scottmg): Crashes VS2013 RC. Upstream bug filed and should be fixed
+// in the next release. http://crbug.com/288948.
+#pragma optimize("", off)
+#endif
+
 #include "primpl.h"
 #include "prbit.h"
 
 #define MULTIPLE_THREADS
 #define ACQUIRE_DTOA_LOCK(n)    PR_Lock(dtoa_lock[n])
 #define FREE_DTOA_LOCK(n)       PR_Unlock(dtoa_lock[n])
 
 static PRLock *dtoa_lock[2];
 
 void _PR_InitDtoa(void)
@@ skipping 3487 matching lines @@
         }
 
         while (*nump != '\0') {
             *bufp++ = *nump++;
         }
         *bufp++ = '\0';
     }
 done:
     PR_DELETE(num);
 }