From 4d5453bc56b8243eb0e16a84d8ba74df0473f450 Mon Sep 17 00:00:00 2001
From: Simon Brand <simon@codeplay.com>
Date: Mon, 3 Sep 2018 13:49:56 +0100
Subject: [PATCH] Add missing define

---
 tl/optional.hpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tl/optional.hpp b/tl/optional.hpp
index a2b27bc..485b416 100644
--- a/tl/optional.hpp
+++ b/tl/optional.hpp
@@ -139,6 +139,10 @@ template <class B, class... Bs>
 struct conjunction<B, Bs...>
     : std::conditional<bool(B::value), conjunction<Bs...>, B>::type {};
 
+#if defined(_LIBCPP_VERSION) && __cplusplus == 201103L
+#define TL_OPTIONAL_LIBCXX_MEM_FN_WORKAROUND
+#endif
+    
 // In C++11 mode, there's an issue in libc++'s std::mem_fn
 // which results in a hard-error when using it in a noexcept expression
 // in some cases. This is a check to workaround the common failing case.