diff --git a/src/mrw/checkcxx11.hxx b/src/mrw/checkcxx11.hxx
index b61a785..63ba99d 100644
--- a/src/mrw/checkcxx11.hxx
+++ b/src/mrw/checkcxx11.hxx
@@ -24,6 +24,7 @@
                when support for C++11 is more common. Only rely on
                this workaround, if you really have to.
                Mac gcc is even worse than on other systems. */
+#          include <tr1/memory>
 #          define MRW__OLD_PRE11_COMPILER
 #          warning you need a C++11 compliant compiler, on gcc: add -std=c++11
 #          warning emulating C++11 - this changes the way you use the library