Compatibility layer to transition from UniquePtr to std::unique_ptr.

Use ART_WITH_STLPORT (enabled for the target) to cause the use of UniquePtr,
for the host switch to std::unique_ptr. For now the type remains called
UniquePtr.
Make dalvik compile with clang on the host, move its build to C++11.

Change-Id: I5ba8d2757904bc089ed62047ea03de3c0853fb12
diff --git a/runtime/base/logging.h b/runtime/base/logging.h
index 6944278..7800cfe 100644
--- a/runtime/base/logging.h
+++ b/runtime/base/logging.h
@@ -25,7 +25,7 @@
 #include <vector>
 #include "base/macros.h"
 #include "log_severity.h"
-#include "UniquePtr.h"
+#include "UniquePtrCompat.h"
 
 #define CHECK(x) \
   if (UNLIKELY(!(x))) \