FreeRTOS compilation fix when no LED present (#1413)

Fixes #1412

libraries/FreeRTOS/keywords.txt

@@ -2,6 +2,8 @@
 # https://arduino.github.io/arduino-cli/library-specification/#keywords
 # Formatted by a single true tab (not spaces)
 
+FreeRTOS	KEYWORD1
+
 # Datatypes (KEYWORD1)
 StackType_t	KEYWORD1
 BaseType_t	KEYWORD1

libraries/FreeRTOS/src/variantHooks.cpp

@@ -216,16 +216,20 @@ void vApplicationTickHook(void) {
     Private function to enable board led to use it in application hooks
 */
 void prvSetMainLedOn(void) {
+#ifdef LED_BUILTIN
     gpio_init(LED_BUILTIN);
     gpio_set_dir(LED_BUILTIN, true);
     gpio_put(LED_BUILTIN, true);
+#endif
 }
 
 /**
     Private function to blink board led to use it in application hooks
 */
 void prvBlinkMainLed(void) {
+#ifdef LED_BUILTIN
     gpio_put(LED_BUILTIN, !gpio_get(LED_BUILTIN));
+#endif
 }
 
 #endif

variants/generic/common.h

@@ -6,7 +6,9 @@
 #define NUM_ANALOG_OUTPUTS  (0u)
 #define ADC_RESOLUTION      (12u)
 
+#ifdef PIN_LED
 #define LED_BUILTIN PIN_LED
+#endif
 
 static const uint8_t D0 = (0u);
 static const uint8_t D1 = (1u);