Refactor all instances of `typedef y x` to the C++11 `using x = y` syntax.

src/IceInst.h

Index: src/IceInst.h
diff --git a/src/IceInst.h b/src/IceInst.h
index 56c5d3a7ac177a14acb1d875c3360e11bebf89e0..80b2bd2622978621b7857b7942f744b321ac7abb 100644
--- a/src/IceInst.h
+++ b/src/IceInst.h
@@ -215,7 +215,7 @@ protected:
   /// mapped to one bit position of the LiveRangesEnded bit vector.
   /// Only the first CHAR_BIT * sizeof(LREndedBits) variables are
   /// tracked this way.
-  typedef uint32_t LREndedBits; // only first 32 src operands tracked, sorry
+  using LREndedBits = uint32_t; // only first 32 src operands tracked, sorry
   LREndedBits LiveRangesEnded;
 };