Update RS485.h

Compiling ModbusLib on an ESP32 board stopp compiling on an compiling error RS485.cpp with  SERIAL_PORT_HARDWARE is not defined.

Here in RS485.cpp is:
#ifdef RS485_SERIAL_PORT
RS485Class RS485(RS485_SERIAL_PORT, RS485_DEFAULT_TX_PIN, RS485_DEFAULT_DE_PIN, RS485_DEFAULT_RE_PIN);
#else
RS485Class RS485(SERIAL_PORT_HARDWARE, RS485_DEFAULT_TX_PIN, RS485_DEFAULT_DE_PIN, RS485_DEFAULT_RE_PIN);
#endif

Thus SERIAL_PORT_HARDWARE should be defined anyhow independently in RS485.h .

Author: bohnelang

Diff for: src/RS485.h

@@ -40,7 +40,6 @@
 #define RS485_DEFAULT_DE_PIN A4
 #define RS485_DEFAULT_RE_PIN A5
 #elif defined(ARDUINO_UNOR4_WIFI) || defined(ARDUINO_UNOR4_MINIMA)
-#define SERIAL_PORT_HARDWARE Serial1
 #define RS485_DEFAULT_DE_PIN 8
 #define RS485_DEFAULT_RE_PIN 7
 #else
@@ -50,6 +49,8 @@
 #endif
 #endif
 
+#define SERIAL_PORT_HARDWARE Serial1
+
 #ifdef CUSTOM_RS485_DEFAULT_DE_PIN
 # define RS485_DEFAULT_DE_PIN CUSTOM_RS485_DEFAULT_DE_PIN
 #endif