Revert "Revert "Upgrade to 5.0.71.48"" DO NOT MERGE

This reverts commit f2e3994fa5148cc3d9946666f0b0596290192b0e,
and updates the x64 makefile properly so it doesn't break that
build.

FPIIM-449

Change-Id: Ib83e35bfbae6af627451c926a9650ec57c045605
(cherry picked from commit 109988c7ccb6f3fd1a58574fa3dfb88beaef6632)
diff --git a/src/compiler/liveness-analyzer.h b/src/compiler/liveness-analyzer.h
index 1e2f85b..9b09724 100644
--- a/src/compiler/liveness-analyzer.h
+++ b/src/compiler/liveness-analyzer.h
@@ -85,6 +85,10 @@
   void Bind(int var) { entries_.push_back(Entry(Entry::kBind, var)); }
   void Checkpoint(Node* node) { entries_.push_back(Entry(node)); }
   void AddPredecessor(LivenessAnalyzerBlock* b) { predecessors_.push_back(b); }
+  LivenessAnalyzerBlock* GetPredecessor() {
+    DCHECK(predecessors_.size() == 1);
+    return predecessors_[0];
+  }
 
  private:
   class Entry {