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/compiler/llvm/llvm_compilation_unit.cc b/compiler/llvm/llvm_compilation_unit.cc
index 78bdb4d..741c2d7 100644
--- a/compiler/llvm/llvm_compilation_unit.cc
+++ b/compiler/llvm/llvm_compilation_unit.cc
@@ -152,7 +152,7 @@
   std::string bitcode;
   DumpBitcodeToString(bitcode);
   std::string filename(StringPrintf("%s/Art%zu.bc", DumpDirectory().c_str(), cunit_id_));
-  UniquePtr<File> output(OS::CreateEmptyFile(filename.c_str()));
+  std::unique_ptr<File> output(OS::CreateEmptyFile(filename.c_str()));
   output->WriteFully(bitcode.data(), bitcode.size());
   LOG(INFO) << ".bc file written successfully: " << filename;
 }
@@ -179,7 +179,7 @@
   if (kDumpELF) {
     // Dump the ELF image for debugging
     std::string filename(StringPrintf("%s/Art%zu.o", DumpDirectory().c_str(), cunit_id_));
-    UniquePtr<File> output(OS::CreateEmptyFile(filename.c_str()));
+    std::unique_ptr<File> output(OS::CreateEmptyFile(filename.c_str()));
     output->WriteFully(elf_object_.data(), elf_object_.size());
     LOG(INFO) << ".o file written successfully: " << filename;
   }