Revert "Revert "Revert "Revert "Remove incorrect android_atomic_...64 use.""""

After fixing b/16874785.

This reverts commit f010a05c7e9a23b6083294aff4a8183ab01f686e.

Change-Id: I1645ca5d6f60595bf5d388913665ce4b8780b26d
diff --git a/include/binder/Binder.h b/include/binder/Binder.h
index ba3ac4b..86628a0 100644
--- a/include/binder/Binder.h
+++ b/include/binder/Binder.h
@@ -17,6 +17,8 @@
 #ifndef ANDROID_BINDER_H
 #define ANDROID_BINDER_H
 
+#include <stdatomic.h>
+#include <stdint.h>
 #include <binder/IBinder.h>
 
 // ---------------------------------------------------------------------------
@@ -69,7 +71,7 @@
 
     class Extras;
 
-            Extras*     mExtras;
+    atomic_uintptr_t    mExtras;  // should be atomic<Extras *>
             void*       mReserved0;
 };