From ef513ef7fbc0c95ff35c71863f70c51a67bef2ee Mon Sep 17 00:00:00 2001
From: Lino Barreca <linobarreca@hotmail.com>
Date: Wed, 15 Jan 2020 05:33:22 +0100
Subject: [PATCH] Fix build error with unsupported reset flags (#16562)

---
 Marlin/src/HAL/HAL_STM32/HAL.cpp | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/Marlin/src/HAL/HAL_STM32/HAL.cpp b/Marlin/src/HAL/HAL_STM32/HAL.cpp
index 1e9129b63f..63db14f723 100644
--- a/Marlin/src/HAL/HAL_STM32/HAL.cpp
+++ b/Marlin/src/HAL/HAL_STM32/HAL.cpp
@@ -95,11 +95,27 @@ void HAL_init() {
 void HAL_clear_reset_source() { __HAL_RCC_CLEAR_RESET_FLAGS(); }
 
 uint8_t HAL_get_reset_source() {
-  if (__HAL_RCC_GET_FLAG(RCC_FLAG_IWDGRST) != RESET) return RST_WATCHDOG;
-  if (__HAL_RCC_GET_FLAG(RCC_FLAG_SFTRST) != RESET)  return RST_SOFTWARE;
-  if (__HAL_RCC_GET_FLAG(RCC_FLAG_PINRST) != RESET)  return RST_EXTERNAL;
-  if (__HAL_RCC_GET_FLAG(RCC_FLAG_PORRST) != RESET)  return RST_POWER_ON;
-  return 0;
+  return
+    #ifdef RCC_FLAG_IWDGRST // Some sources may not exist...
+      RESET != __HAL_RCC_GET_FLAG(RCC_FLAG_IWDGRST)  ? RST_WATCHDOG :
+    #endif
+    #ifdef RCC_FLAG_IWDG1RST
+      RESET != __HAL_RCC_GET_FLAG(RCC_FLAG_IWDG1RST) ? RST_WATCHDOG :
+    #endif
+    #ifdef RCC_FLAG_IWDG2RST
+      RESET != __HAL_RCC_GET_FLAG(RCC_FLAG_IWDG2RST) ? RST_WATCHDOG :
+    #endif
+    #ifdef RCC_FLAG_SFTRST
+      RESET != __HAL_RCC_GET_FLAG(RCC_FLAG_SFTRST)   ? RST_SOFTWARE :
+    #endif
+    #ifdef RCC_FLAG_PINRST
+      RESET != __HAL_RCC_GET_FLAG(RCC_FLAG_PINRST)   ? RST_EXTERNAL :
+    #endif
+    #ifdef RCC_FLAG_PORRST
+      RESET != __HAL_RCC_GET_FLAG(RCC_FLAG_PORRST))  ? RST_POWER_ON :
+    #endif
+    0
+  ;
 }
 
 void _delay_ms(const int delay_ms) { delay(delay_ms); }