Subzero: Use C++11 member initializers where practical.

src/IceBrowserCompileServer.h

 //===- subzero/src/IceBrowserCompileServer.h - Browser server ---*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the browser-specific compile server.
@@ skipping 82 matching lines @@
   private:
     std::string Buffer;
     llvm::raw_string_ostream StrBuf;
   };
   // This currently only handles a single compile request, hence one copy
   // of the state.
   std::unique_ptr<GlobalContext> Ctx;
   // A borrowed reference to the current InputStream. The compiler owns
   // the actual reference so the server must be careful not to access
   // after the compiler is done.
-  llvm::QueueStreamer *InputStream;
+  llvm::QueueStreamer *InputStream = nullptr;
   std::unique_ptr<Ostream> LogStream;
   std::unique_ptr<llvm::raw_fd_ostream> EmitStream;
   std::unique_ptr<StringStream> ErrorStream;
   std::unique_ptr<ELFStreamer> ELFStream;
   ClFlags Flags;
   ClFlagsExtra ExtraFlags;
   std::thread CompileThread;
   std::atomic<bool> HadError;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEBROWSERCOMPILESERVER_H