Add test of macro-generated inline namespace

Author: dtolnay

bindgen-tests/tests/expectations/tests/inline_namespace_macro.rs

@@ -0,0 +1,9 @@
+// bindgen-flags: --enable-cxx-namespaces -- -std=c++11
+
+#include "namespace/nsdefine.h"
+
+BEGIN_NAMESPACE
+
+class duration {};
+
+END_NAMESPACE

bindgen-tests/tests/headers/inline_namespace_macro.hpp

@@ -0,0 +1,4 @@
+#pragma once
+
+#define BEGIN_NAMESPACE namespace repro { inline namespace __1 {
+#define END_NAMESPACE } }