Small fixes to iot code

iot/Makefile

@@ -3,5 +3,5 @@ FILES=main.c brokers/mqtt.c brokers/amqp.c devices/temperature.c devices/display
 # libgpiod version must be < 2.0
 
 all: $(FILES)
-	$(CC) -lmosquitto -lrabbitmq -lpthread -li2c -lgpiod $(FILES)
+	$(CC) -lmosquitto -lrabbitmq -pthread -li2c -lgpiod $(FILES)
 

iot/main.c

@@ -24,6 +24,8 @@ void *sound_alarm(void *arg)
 		usleep(delay * 2 * length);
 	}
 
+	destroy_buzzer(buzzer);
+
 	return NULL;
 }