It helps if you write macros correctly

src/google/protobuf/stubs/hash.h

@@ -42,8 +42,8 @@
 #define GOOGLE_PROTOBUF_HAVE_HASH_SET 1
 
 // Use C++11 unordered_{map|set} if available.
-#if ((_LIBCPP_STD_VER >= 11) ||
-     (((__cplusplus >= 201103L) || defined(__GXX_EXPERIMENTAL_CXX0X)) &&
+#if ((_LIBCPP_STD_VER >= 11) || \
+     (((__cplusplus >= 201103L) || defined(__GXX_EXPERIMENTAL_CXX0X)) && \
       (__GLIBCXX__ > 20090421)))
 # define GOOGLE_PROTOBUF_HAS_CXX11_HASH