diff --git a/src/mrw/checkcxx11.hxx b/src/mrw/checkcxx11.hxx
index 9832599..19b14a0 100644
--- a/src/mrw/checkcxx11.hxx
+++ b/src/mrw/checkcxx11.hxx
@@ -87,6 +87,9 @@ namespace std {
        };
      }
 #  else
+#    ifdef __APPLE__
+#      error hidden apple?
+#    endif
 #    warning found C++11 support, everything is fine
 #  endif