add boost on mac

macx64/include/boost/callable_traits/detail/forward_declarations.hpp

@@ -0,0 +1,54 @@
+#ifndef BOOST_CLBL_TRTS_DETAIL_FORWARD_DECLARATIONS
+#define BOOST_CLBL_TRTS_DETAIL_FORWARD_DECLARATIONS
+#include <boost/callable_traits/detail/config.hpp>
+#include <boost/callable_traits/detail/default_callable_traits.hpp>
+
+namespace boost { namespace callable_traits { namespace detail {
+
+template<typename T>
+struct function;
+
+template<typename T>
+struct has_normal_call_operator
+{
+    template<typename N, N Value>
+    struct check { check(std::nullptr_t) {} };
+
+    template<typename U>
+    static std::int8_t test(
+        check<decltype(&U::operator()), &U::operator()>);
+
+    template<typename>
+    static std::int16_t test(...);
+
+    static constexpr bool value =
+        sizeof(test<T>(nullptr)) == sizeof(std::int8_t);
+};
+
+struct callable_dummy {
+    void operator()() {}
+};
+
+template<typename T>
+using default_to_function_object = typename std::conditional<
+    has_normal_call_operator<T>::value,
+    T, callable_dummy>::type;
+
+template<typename T>
+struct pmf;
+
+template<typename T>
+struct pmd;
+
+template<typename F, typename T = typename std::remove_reference<F>::type>
+using function_object_base = typename std::conditional<
+    has_normal_call_operator<T>::value,
+    pmf<decltype(&default_to_function_object<T>::operator())>,
+    default_callable_traits<T>>::type;
+
+template<typename T, typename Base = function_object_base<T>>
+struct function_object;
+
+}}} // namespace boost::callable_traits::detail
+
+#endif // #ifndef BOOST_CLBL_TRTS_DETAIL_FORWARD_DECLARATIONS