--- a/memory/build/mozmemory_wrap.h
+++ b/memory/build/mozmemory_wrap.h
@@ -87,19 +87,16 @@
  *   char* strdup_impl(const char *)
  * That implementation would call malloc by using "malloc_impl".
  */
 
 #ifndef MOZ_MEMORY
 #  error Should only include mozmemory_wrap.h when MOZ_MEMORY is set.
 #endif
 
-#if defined(MOZ_JEMALLOC_IMPL) && !defined(MOZ_MEMORY_IMPL)
-#  define MOZ_MEMORY_IMPL
-#endif
 #if defined(MOZ_MEMORY_IMPL) && !defined(IMPL_MFBT)
 #  ifdef MFBT_API /* mozilla/Types.h was already included */
 #    error mozmemory_wrap.h has to be included before mozilla/Types.h when MOZ_MEMORY_IMPL is set and IMPL_MFBT is not.
 #  endif
 #  define IMPL_MFBT
 #endif
 
 #include "mozilla/Types.h"

--- a/memory/mozjemalloc/moz.build
+++ b/memory/mozjemalloc/moz.build
@@ -8,17 +8,17 @@ EXPORTS += [
     'mozjemalloc_types.h',
 ]
 
 SOURCES += [
     'mozjemalloc.cpp',
 ]
 FINAL_LIBRARY = 'memory'
 
-DEFINES['MOZ_JEMALLOC_IMPL'] = True
+DEFINES['MOZ_MEMORY_IMPL'] = True
 
 LOCAL_INCLUDES += [
     '/memory/build',
 ]
 
 if CONFIG['GNU_CXX']:
     # too many warnings from functions generated through rb_wrab from rb.h.
     CXXFLAGS += ['-Wno-unused-function',