--- a/memory/mozalloc/mozalloc.h
+++ b/memory/mozalloc/mozalloc.h
@@ -38,19 +38,17 @@
 #if defined(MOZ_ALWAYS_INLINE_EVEN_DEBUG)
 #  define MOZALLOC_INLINE MOZ_ALWAYS_INLINE_EVEN_DEBUG
 #elif defined(HAVE_FORCEINLINE)
 #  define MOZALLOC_INLINE __forceinline
 #else
 #  define MOZALLOC_INLINE inline
 #endif
 
-#if defined(__cplusplus)
-extern "C" {
-#endif /* ifdef __cplusplus */
+MOZ_BEGIN_EXTERN_C
 
 /*
  * We need to use malloc_impl and free_impl in this file when they are
  * defined, because of how mozglue.dll is linked on Windows, where using
  * malloc/free would end up using the symbols from the MSVCRT instead of
  * ours.
  */
 #ifndef free_impl
@@ -115,19 +113,17 @@ MFBT_API void* moz_xmemalign(size_t boun
 
 
 #if defined(HAVE_VALLOC)
 MFBT_API void* moz_xvalloc(size_t size)
     MOZ_ALLOCATOR;
 #endif /* if defined(HAVE_VALLOC) */
 
 
-#ifdef __cplusplus
-} /* extern "C" */
-#endif /* ifdef __cplusplus */
+MOZ_END_EXTERN_C
 
 
 #ifdef __cplusplus
 
 /*
  * We implement the default operators new/delete as part of
  * libmozalloc, replacing their definitions in libstdc++.  The
  * operator new* definitions in libmozalloc will never return a NULL