#ifndef => #if !PIN_EXISTS

Marlin/src/HAL/HAL_STM32F1/HAL_spi_Stm32f1.cpp

@@ -76,7 +76,7 @@ static SPISettings spiConfig;
  * @details Only configures SS pin since libmaple creates and initialize the SPI object
  */
 void spiBegin() {
-  #ifndef SS_PIN
+  #if !PIN_EXISTS(SS)
     #error "SS_PIN not defined!"
   #endif
   SET_OUTPUT(SS_PIN);