Add more ASIO error mapping code for apple

Author: arturl

Release/src/http/client/http_linux.cpp

@@ -73,8 +73,14 @@ namespace web { namespace http
                         // We need to correct inaccurate ASIO error code base on context information
                         switch (context)
                         {
+#if defined(__APPLE__)                      
+                        case httpclient_errorcode_context::writeheader:
+                            if (ec == boost::system::errc::broken_pipe) 
+                                errorcodeValue = make_error_code(std::errc::host_unreachable).value();
+                            break;
+#endif
                         case httpclient_errorcode_context::connect:
-                            if (ec == boost::system::errc::connection_refused)
+                            if (ec == boost::system::errc::connection_refused) 
                                 errorcodeValue = make_error_code(std::errc::host_unreachable).value();
                             break;
                         case httpclient_errorcode_context::readheader: