Merge pull request #172 from tanderson-google/libcpp-win

Fix build with Windows/libc++
diff --git a/cpp/src/util/size.h b/cpp/src/util/size.h
index 4128f20..539f105 100644
--- a/cpp/src/util/size.h
+++ b/cpp/src/util/size.h
@@ -34,9 +34,9 @@
 //
 // https://docs.microsoft.com/en-us/cpp/visual-cpp-language-conformance
 
-#if __cpp_lib_nonmember_container_access >= 201411 || \
-    (_LIBCPP_VERSION >= 1101 && _LIBCPP_STD_VER > 14) || \
-    (!defined(_LIBCPP_STD_VER) && _MSC_VER >= 1900)
+#if (_LIBCPP_VERSION >= 1101 && _LIBCPP_STD_VER > 14) || \
+    (!defined(_LIBCPP_STD_VER) &&                        \
+     (_MSC_VER >= 1900 || __cpp_lib_nonmember_container_access >= 201411))
 
 using std::size;