Fix broken build on OS X (#35)

Signed-off-by: Gregory Brail <[email protected]>

Author: gbrail

.gitignore

@@ -0,0 +1 @@
+/bazel-*

WORKSPACE

@@ -35,6 +35,7 @@ git_repository(
     name = "com_google_protobuf",
     commit = "655310ca192a6e3a050e0ca0b7084a2968072260",
     remote = "https://github.com/protocolbuffers/protobuf",
+    shallow_since = "1565024848 -0700",
 )
 
 http_archive(

include/proxy-wasm/compat.h

@@ -26,21 +26,21 @@
 #endif
 
 namespace proxy_wasm {
-#ifndef __cpp_lib_optional
-template <typename T> using optional = absl::optional<T>;
-// Only available in C++17
-// inline constexpr absl::nullopt_t nullopt = absl::nullopt;
-#define PROXY_WASM_NULLOPT absl::nullopt
-#else
+#if __cplusplus >= 201703L
+
 template <typename T> using optional = std::optional<T>;
 // Only available in C++17
 // inline constexpr std::nullopt_t nullopt = std::nullopt;
 #define PROXY_WASM_NULLOPT std::nullopt
-#endif
+using string_view = std::string_view;
 
-#ifndef __cpp_lib_string_view
-using string_view = absl::string_view;
 #else
-using string_view = std::string_view;
+
+template <typename T> using optional = absl::optional<T>;
+// Only available in C++17
+// inline constexpr absl::nullopt_t nullopt = absl::nullopt;
+#define PROXY_WASM_NULLOPT absl::nullopt
+using string_view = absl::string_view;
+
 #endif
 } // namespace proxy_wasm