update_engine_stable_android: Use noreturn am: 5d7a1de410 am: 783be0bd53 am: 6eaa5103c2

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/1393752

Change-Id: I5ddd6573d86a554f9f0eee041490e748affd2b4d
diff --git a/stable/update_engine_stable_client.cc b/stable/update_engine_stable_client.cc
index c466c42..da203c4 100644
--- a/stable/update_engine_stable_client.cc
+++ b/stable/update_engine_stable_client.cc
@@ -50,10 +50,9 @@
               "",
               "A list of key-value pairs, one element of the list per line.");
 
-int Exit(int return_code) {
+[[noreturn]] int Exit(int return_code) {
   LOG(INFO) << "Exit: " << return_code;
   exit(return_code);
-  __builtin_unreachable();
 }
 // Called whenever the UpdateEngine daemon dies.
 void UpdateEngineServiceDied(void*) {
@@ -98,7 +97,6 @@
   Exit((code == ErrorCode::kSuccess || code == ErrorCode::kUpdatedButNotActive)
            ? EX_OK
            : EX_SOFTWARE);
-  __builtin_unreachable();
 }
 
 int UpdateEngineClientAndroid::Run() {