Use a macro for HAL header redirection (#10380)

Marlin/src/HAL/HAL_AVR/HAL.h

@@ -43,6 +43,7 @@
 #include <avr/interrupt.h>
 #include <avr/io.h>
 
+#include "../HAL_SPI.h"
 #include "fastio_AVR.h"
 #include "watchdog_AVR.h"
 #include "math_AVR.h"

Marlin/src/HAL/HAL_AVR/endstop_interrupts.h

@@ -41,6 +41,17 @@
 #include "../../core/macros.h"
 #include <stdint.h>
 
+volatile uint8_t e_hit = 0; // Different from 0 when the endstops should be tested in detail.
+                            // Must be reset to 0 by the test function when finished.
+
+// This is what is really done inside the interrupts.
+FORCE_INLINE void endstop_ISR_worker( void ) {
+  e_hit = 2; // Because the detection of a e-stop hit has a 1 step debouncer it has to be called at least twice.
+}
+
+// One ISR for all EXT-Interrupts
+void endstop_ISR(void) { endstop_ISR_worker(); }
+
 /**
  * Patch for pins_arduino.h (...\Arduino\hardware\arduino\avr\variants\mega\pins_arduino.h)
  *