Subzero: Improve class definition hygiene.

src/IceTranslator.h

Index: src/IceTranslator.h
diff --git a/src/IceTranslator.h b/src/IceTranslator.h
index bc9a933dd22b7063bd19a9698d2fa5368e01d8e0..d039148288147efbcfae3f0602fdd4df8def4952 100644
--- a/src/IceTranslator.h
+++ b/src/IceTranslator.h
@@ -30,11 +30,12 @@ class GlobalContext;
 // other intermediate representations down to ICE, and then call the appropriate
 // (inherited) methods to convert ICE into machine instructions.
 class Translator {
+  Translator() = delete;
   Translator(const Translator &) = delete;
   Translator &operator=(const Translator &) = delete;
 
 public:
-  Translator(GlobalContext *Ctx);
+  explicit Translator(GlobalContext *Ctx);
 
   ~Translator();
   const ErrorCode &getErrorStatus() const { return ErrorStatus; }