+} // namespace folly
+
+// Define FOLLY_USE_CPP14_CONSTEXPR to be true if the compiler's C++14
+// constexpr support is "good enough".
+#ifndef FOLLY_USE_CPP14_CONSTEXPR
+#if defined(__clang__)
+#define FOLLY_USE_CPP14_CONSTEXPR __cplusplus >= 201300L
+#elif defined(__GNUC__)
+#define FOLLY_USE_CPP14_CONSTEXPR __cplusplus >= 201304L
+#else
+#define FOLLY_USE_CPP14_CONSTEXPR 0 // MSVC?
+#endif
+#endif
+
+#if FOLLY_USE_CPP14_CONSTEXPR
+#define FOLLY_CPP14_CONSTEXPR constexpr
+#else
+#define FOLLY_CPP14_CONSTEXPR inline
+#endif
+
+#if __cpp_coroutines >= 201703L || (_MSC_VER && _RESUMABLE_FUNCTIONS_SUPPORTED)
+#define FOLLY_HAS_COROUTINES 1
+#endif
+
+// MSVC 2017.5
+#if __cpp_noexcept_function_type >= 201510 || _MSC_FULL_VER >= 191225816
+#define FOLLY_HAVE_NOEXCEPT_FUNCTION_TYPE 1
+#endif