Enable TCMalloc doubly-linked freelist in release builds

third_party/tcmalloc/chromium/src/free_list.cc

 // Copyright (c) 2011, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
@@ skipping 41 matching lines @@
 // -In singly linked lists, the |next| pointer is stored in the first N
 // bytes of the node.
 //
 // For both types of lists: when a pop operation is performed on a non
 // empty list, the new list head becomes that which is pointed to by
 // the former head's |next| pointer.  If the list is doubly linked, the
 // new head |previous| pointer gets changed from pointing to the former
 // head to NULL.
 
 
-#ifdef TCMALLOC_USE_DOUBLYLINKED_FREELIST
-
 #include <stddef.h>
 #include "free_list.h"
 
+#if defined(TCMALLOC_USE_DOUBLYLINKED_FREELIST)
+
 // TODO(jar): We should use C++ rather than a macro here.
 #define MEMORY_CHECK(v1, v2) \
   if (v1 != v2) CRASH("Memory corruption detected.\n")
 
 namespace {
 void EnsureNonLoop(void* node, void* next) {
   // We only have time to do minimal checking.  We don't traverse the list, but
   // only look for an immediate loop (cycle back to ourself).
   if (node != next) return;
   CRASH("Circular loop in list detected: %p\n", next);
@@ skipping 143 matching lines @@
 
 namespace {
 
 inline void FL_SetNext(void *t, void *n) {
   tcmalloc::SLL_SetNext(t,n);
 }
 
 }
 
 #endif // TCMALLOC_USE_DOUBLYLINKED_FREELIST