diff --git a/src/common/imageio_exr.hh b/src/common/imageio_exr.hh
index 6023dc4..7dae59f 100644
--- a/src/common/imageio_exr.hh
+++ b/src/common/imageio_exr.hh
@@ -21,10 +21,18 @@
 #include "common/image.h"
 #include "common/mipmap_cache.h"
 
-#if __cplusplus >= 201103L || defined(__clang__)
+#ifndef __has_include
+#warning "__has_include not defined"
+#define __has_include(x) 1
+#endif
+
+#if __has_include(<memory>)
 #include <memory>
 #else
 #include <tr1/memory>
+namespace std {
+  using namespace tr1;
+}
 #endif
 
 #include <OpenEXR/ImfFrameBuffer.h>
@@ -60,11 +68,7 @@ public:
   }
 
   uint32_t size;
-#if __cplusplus >= 201103L || defined(__clang__)
   std::shared_ptr<uint8_t> data;
-#else
-  std::tr1::shared_ptr<uint8_t> data;
-#endif
 };