--- a/memory/build/mozjemalloc.cpp
+++ b/memory/build/mozjemalloc.cpp
@@ -153,18 +153,16 @@
 #include <stdio.h>
 #include <string.h>
 #include <algorithm>
 
 using namespace mozilla;
 
 #ifdef XP_WIN
 
-// Some defines from the CRT internal headers that we need here.
-#define _CRT_SPINCOUNT 5000
 #include <io.h>
 #include <windows.h>
 #include <intrin.h>
 
 #define STDERR_FILENO 2
 
 // Implement getenv without using malloc.
 static char mozillaMallocOptionsBuf[64];
@@ -1299,17 +1297,17 @@ pthread_atfork(void (*)(void), void (*)(
 // cases. We also can't use constructors, because for statics, they would fire
 // after the first use of malloc, resetting the locks.
 
 // Initializes a mutex. Returns whether initialization succeeded.
 bool
 Mutex::Init()
 {
 #if defined(XP_WIN)
-  if (!InitializeCriticalSectionAndSpinCount(&mMutex, _CRT_SPINCOUNT)) {
+  if (!InitializeCriticalSectionAndSpinCount(&mMutex, 5000)) {
     return false;
   }
 #elif defined(XP_DARWIN)
   mMutex = OS_SPINLOCK_INIT;
 #elif defined(XP_LINUX) && !defined(ANDROID)
   pthread_mutexattr_t attr;
   if (pthread_mutexattr_init(&attr) != 0) {
     return false;