Index: compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h
===================================================================
--- compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h
+++ compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h
@@ -259,7 +259,9 @@
 # define NOEXCEPT throw()
 #endif
 
-#if __has_cpp_attribute(clang::fallthrough)
+#if __has_cpp_attribute(fallthrough)
+#  define FALLTHROUGH [[fallthrough]]
+#elif __has_cpp_attribute(clang::fallthrough)
 #  define FALLTHROUGH [[clang::fallthrough]]
 #else
 #  define FALLTHROUGH