8182299: Enable disabled clang warnings, build on OSX 10 + Xcode 8
8182656: Make the required changes in GC code to build on OSX 10 + Xcode 8
8182657: Make the required changes in Runtime code to build on OSX 10 + Xcode 8
8182658: Make the required changes in Compiler code to build on OSX 10 + Xcode 8

Co-authored-by: Paul Hohensee <hohensee@amazon.com>
Reviewed-by: jwilhelm, ehelin, phh
diff --git a/hotspot/src/share/vm/runtime/relocator.cpp b/hotspot/src/share/vm/runtime/relocator.cpp
index df1911f..3af2012 100644
--- a/hotspot/src/share/vm/runtime/relocator.cpp
+++ b/hotspot/src/share/vm/runtime/relocator.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -247,6 +247,8 @@
           ShouldNotReachHere();
       }
     }
+    default:
+      break;
   }
   return instruction_length_at(bci);
 }