Now we have a proper C++ library, use std::unique_ptr.

Also remove the Android.libcxx.mk and other bits of stlport compatibility
mechanics.

Change-Id: Icdf7188ba3c79cdf5617672c1cfd0a68ae596a61
diff --git a/runtime/jni_internal.cc b/runtime/jni_internal.cc
index 17a3de4..80969bf 100644
--- a/runtime/jni_internal.cc
+++ b/runtime/jni_internal.cc
@@ -19,6 +19,7 @@
 #include <dlfcn.h>
 
 #include <cstdarg>
+#include <memory>
 #include <utility>
 #include <vector>
 
@@ -49,7 +50,6 @@
 #include "ScopedLocalRef.h"
 #include "thread.h"
 #include "utf.h"
-#include "UniquePtrCompat.h"
 #include "well_known_classes.h"
 
 namespace art {