Make optional build

Change-Id: I57b2f5de0e922c876166443899c355366720a5b8
diff --git a/third_party/optional/tests/bases.cpp b/third_party/optional/tests/bases.cpp
index cff7819..09623ea 100644
--- a/third_party/optional/tests/bases.cpp
+++ b/third_party/optional/tests/bases.cpp
@@ -2,8 +2,7 @@
 #include "optional.hpp"
 
 // Old versions of GCC don't have the correct trait names. Could fix them up if needs be.
-#if (defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ <= 9 &&              \
-     !defined(__clang__))
+#ifdef TL_OPTIONAL_GCC49
 // nothing for now
 #else
 TEST_CASE("Triviality", "[bases.triviality]") {