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/compiler/compiled_method.h b/compiler/compiled_method.h
index 844b53c..c3c9961 100644
--- a/compiler/compiled_method.h
+++ b/compiler/compiled_method.h
@@ -22,7 +22,7 @@
 
 #include "instruction_set.h"
 #include "utils.h"
-#include "UniquePtr.h"
+#include "UniquePtrCompat.h"
 
 namespace llvm {
   class Function;