add noexcept specifier for Boost 1.55

asyncmsg/Error.h

@@ -26,7 +26,7 @@ public:
 
   static ErrorCategory& instance();
 
-  const char* name() const;
+  const char* name() const noexcept;
   std::string message(int value) const;
 
 private:

src/Error.cxx

@@ -10,7 +10,7 @@ ErrorCategory& ErrorCategory::instance()
   return s_instance;
 }
 
-const char* ErrorCategory::name() const
+const char* ErrorCategory::name() const noexcept
 {
   return "asyncmsg";
 }