Fix OS X compilation warnings.

Test/Checksum.cc

@@ -10,7 +10,7 @@
 namespace Test {
 namespace Checksum {
 
-extern Level run_lvl = L_NONE;
+Level run_lvl = L_NONE;
 
 namespace {
 
@@ -31,7 +31,7 @@ const Registry& registry()
 // class Checksum implementation
 
 Object::Object(const char* const _name, const Level _lvl)
-  : name_(_name), lvl_(_lvl)
+  : lvl_(_lvl), name_(_name)
 {
   auto pos = registry_modify().emplace(name_, this);
   if (!pos.second)
@@ -128,6 +128,7 @@ Difference Object::compare(
     // HANG replaced by gracious failure!
     case Result::FAILURE: DIFFERENCE(IMPROVED); break; 
     case Result::CRASH: DIFFERENCE(SUSPICIOUS); break; // HANG is now CRASH!
+    default: ; // disable warnings
     };
     break;
   }