ARM64: Fix ASM_LOCATION and the like.

src/checks.h

Index: src/checks.h
diff --git a/src/checks.h b/src/checks.h
index bc599acb1d136c5c91a2f5934d8954199d2b5463..c3153363dd1f4a17cde0d93127b4d16008682178 100644
--- a/src/checks.h
+++ b/src/checks.h
@@ -8,6 +8,7 @@
 #include <string.h>
 
 #include "../include/v8stdint.h"
+#include "base/build_config.h"
 
 extern "C" void V8_Fatal(const char* file, int line, const char* format, ...);
 
@@ -30,7 +31,8 @@ extern "C" void V8_Fatal(const char* file, int line, const char* format, ...);
 #endif
 
 // Simulator specific helpers.
-#if defined(USE_SIMULATOR) && defined(V8_TARGET_ARCH_ARM64)
+// We can't use USE_SIMULATOR here because it isn't defined yet.
+#if V8_TARGET_ARCH_ARM64 && !V8_HOST_ARCH_ARM64
   // TODO(all): If possible automatically prepend an indicator like
   // UNIMPLEMENTED or LOCATION.
   #define ASM_UNIMPLEMENTED(message)                                         \