correct compiler warnings

#189

User_config.h

@@ -34,8 +34,10 @@
 /*-------------DEFINE YOUR NETWORK PARAMETERS BELOW----------------*/
 //MQTT Parameters definition
 //#define mqtt_server_name "www.mqtt_broker.com" // instead of defining the server by its IP you can define it by its name, uncomment this line and set the correct MQTT server host name
-#define mqtt_user "your_username" // not compulsory only if your broker needs authentication
-#define mqtt_pass "your_password" // not compulsory only if your broker needs authentication
+char mqtt_user[20] = "your_username"; // not compulsory only if your broker needs authentication
+char mqtt_pass[20] = "your_password"; // not compulsory only if your broker needs authentication
+char mqtt_server[40] = "192.168.1.17";
+char mqtt_port[6] = "1883";
 #define Gateway_Name "OpenMQTTGateway"
 #define WifiManager_password "your_password"
 #define version_Topic "home/" Gateway_Name "/version"
@@ -45,8 +47,6 @@
 #define will_Message "Offline"
 #define Gateway_AnnouncementMsg "Online"
 //#define MDNS_SD //comment if you don't want to use mdns for discovering automatically your ip server, please note that MDNS with ESP32 can cause the BLE to not work
-char mqtt_server[40] = "192.168.1.17";
-char mqtt_port[6] = "1883";
 
 //set minimu quality of signal so it ignores AP's under that quality
 #define MinimumWifiSignalQuality 8